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Aon plc – ‘10-K’ for 12/31/21 – ‘EX-101.LAB’

On:  Friday, 2/18/22, at 4:07pm ET   ·   For:  12/31/21   ·   Accession #:  1628280-22-3180   ·   File #:  1-07933

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  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/18/22  Aon plc                           10-K       12/31/21  141:20M                                    Workiva Inc Wde… FA01/FA

Annual Report   —   Form 10-K

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   2.13M 
 2: EX-10.20    Material Contract                                   HTML    283K 
 3: EX-10.50    Material Contract                                   HTML     50K 
 4: EX-10.51    Material Contract                                   HTML     50K 
 5: EX-10.64    Material Contract                                   HTML     42K 
 6: EX-10.74    Material Contract                                   HTML     43K 
 7: EX-21.1     Subsidiaries List                                   HTML    194K 
 8: EX-22.1     Published Report re: Matters Submitted to a Vote    HTML     42K 
                of Security Holders                                              
 9: EX-23       Consent of Expert or Counsel                        HTML     43K 
10: EX-31.1     Certification -- §302 - SOA'02                      HTML     43K 
11: EX-31.2     Certification -- §302 - SOA'02                      HTML     43K 
12: EX-32.1     Certification -- §906 - SOA'02                      HTML     40K 
13: EX-32.2     Certification -- §906 - SOA'02                      HTML     40K 
19: R1          Cover                                               HTML    139K 
20: R2          Audit Information                                   HTML     44K 
21: R3          Consolidated Statements of Income                   HTML    126K 
22: R4          Consolidated Statements of Comprehensive Income     HTML     92K 
23: R5          Consolidated Statements of Financial Position       HTML    165K 
24: R6          Consolidated Statements of Financial Position       HTML     45K 
                (Parenthetical)                                                  
25: R7          Consolidated Statements of Shareholders' Equity     HTML    145K 
26: R8          Consolidated Statements of Shareholders' Equity     HTML     41K 
                (Parenthetical)                                                  
27: R9          Consolidated Statements of Cash Flows               HTML    139K 
28: R10         Basis of Presentation                               HTML    107K 
29: R11         Summary of Significant Accounting Principles and    HTML     92K 
                Practices                                                        
30: R12         Revenue from Contracts with Customers               HTML     89K 
31: R13         Other Financial Data                                HTML    119K 
32: R14         Acquisitions and Dispositions of Businesses         HTML     59K 
33: R15         Goodwill and Other Intangible Assets                HTML     73K 
34: R16         Debt                                                HTML     94K 
35: R17         Lease Commitments                                   HTML    191K 
36: R18         Income Taxes                                        HTML    176K 
37: R19         Shareholders' Equity                                HTML    120K 
38: R20         Employee Benefits                                   HTML    447K 
39: R21         Share-Based Compensation Plans                      HTML     88K 
40: R22         Derivatives and Hedging                             HTML     83K 
41: R23         Fair Value Measurements and Financial Instruments   HTML    107K 
42: R24         Claims, Lawsuits and Other Contingencies            HTML     61K 
43: R25         Segment Information                                 HTML     57K 
44: R26         Summary of Significant Accounting Principles and    HTML    153K 
                Practices (Policies)                                             
45: R27         Basis of Presentation (Tables)                      HTML    100K 
46: R28         Summary of Significant Accounting Principles and    HTML     73K 
                Practices (Tables)                                               
47: R29         Revenue from Contracts with Customers (Tables)      HTML     87K 
48: R30         Other Financial Data (Tables)                       HTML    128K 
49: R31         Acquisitions and Dispositions of Businesses         HTML     50K 
                (Tables)                                                         
50: R32         Goodwill and Other Intangible Assets (Tables)       HTML     83K 
51: R33         Debt (Tables)                                       HTML     89K 
52: R34         Lease Commitments (Tables)                          HTML    139K 
53: R35         Income Taxes (Tables)                               HTML    179K 
54: R36         Shareholders' Equity (Tables)                       HTML    121K 
55: R37         Employee Benefits (Tables)                          HTML    451K 
56: R38         Share-Based Compensation Plans (Tables)             HTML     89K 
57: R39         Derivatives and Hedging (Tables)                    HTML     81K 
58: R40         Fair Value Measurements and Financial Instruments   HTML     96K 
                (Tables)                                                         
59: R41         Segment Information (Tables)                        HTML     52K 
60: R42         Basis of Presentation - Additional Information      HTML     55K 
                (Details)                                                        
61: R43         Basis of Presentation - Revision of Previously      HTML     70K 
                Issued Financial Statements (Details)                            
62: R44         Summary of Significant Accounting Principles and    HTML     58K 
                Practices - Additional Information (Details)                     
63: R45         Summary of Significant Accounting Principles and    HTML     58K 
                Practices - Property, Plant and Equipment                        
                (Details)                                                        
64: R46         Summary of Significant Accounting Principles and    HTML     52K 
                Practices - Intangible Assets (Details)                          
65: R47         Revenue from Contracts with Customers -             HTML     70K 
                Disaggregation of Revenue (Details)                              
66: R48         Revenue from Contracts with Customers - Contract    HTML     55K 
                Assets Rollforward (Details)                                     
67: R49         Other Financial Data - Schedule of Other Income     HTML     57K 
                (Details)                                                        
68: R50         Other Financial Data - Schedule of Allowance for    HTML     74K 
                Doubtful Accounts (Details)                                      
69: R51         Other Financial Data - Schedule of Other Current    HTML     50K 
                Assets (Details)                                                 
70: R52         Other Financial Data - Components of Fixed Assets,  HTML     64K 
                Net (Details)                                                    
71: R53         Other Financial Data - Schedule of Other            HTML     52K 
                Non-current Assets (Details)                                     
72: R54         Other Financial Data - Schedule of Other Current    HTML     54K 
                Liabilities (Details)                                            
73: R55         Other Financial Data - Schedule of Other            HTML     55K 
                Non-current Liabilities (Details)                                
74: R56         Acquisitions and Dispositions of Businesses -       HTML     73K 
                Completed Acquisitions (Details)                                 
75: R57         Acquisitions and Dispositions of Businesses -       HTML     72K 
                Schedule of Net Assets Acquired (Details)                        
76: R58         Acquisitions and Dispositions of Businesses -       HTML     43K 
                Completed Dispositions (Details)                                 
77: R59         Acquisitions and Dispositions of Businesses -       HTML     40K 
                Other Significant Activity (Details)                             
78: R60         Goodwill and Other Intangible Assets - Schedule of  HTML     49K 
                changes in the net carrying amount of goodwill                   
                (Details)                                                        
79: R61         Goodwill and Other Intangible Assets - Schedule of  HTML     60K 
                other intangible assets by asset class (Details)                 
80: R62         Goodwill and Other Intangible Assets - Schedule of  HTML     55K 
                estimated future amortization expense on                         
                intangible assets (Details)                                      
81: R63         Debt - Summary of outstanding debt (Details)        HTML    118K 
82: R64         Debt - Narrative (Details)                          HTML    106K 
83: R65         Debt - Repayments of long-term debt (Details)       HTML     66K 
84: R66         Debt - Schedule of Commercial Paper (Details)       HTML     47K 
85: R67         Lease Commitments - Assets and Liabilities of       HTML     67K 
                Lessee (Details)                                                 
86: R68         Lease Commitments - Lease Costs (Details)           HTML     57K 
87: R69         Lease Commitments - Lease Terms and Assumptions     HTML     50K 
                (Details)                                                        
88: R70         Lease Commitments - Cash Flow of Lessee (Details)   HTML     54K 
89: R71         Lease Commitments - Lease Maturity (Details)        HTML     98K 
90: R72         Income Taxes - Income from continuing operations    HTML     75K 
                before income tax (Details)                                      
91: R73         Income Taxes - Narrative (Details)                  HTML     57K 
92: R74         Income Taxes - Reconciliation of the income tax     HTML     79K 
                provisions based on the U.S. statutory corporate                 
                tax rate to the provisions reflected in the                      
                Consolidated Financial Statements (Details)                      
93: R75         Income Taxes - Components of Aon's deferred tax     HTML     89K 
                assets and liabilities (Details)                                 
94: R76         Income Taxes - Deferred income taxes (assets and    HTML     46K 
                liabilities netted by jurisdiction) as classified                
                in the Consolidated Statements of Financial                      
                Position (Details)                                               
95: R77         Income Taxes Operating Loss Carryforwards           HTML     56K 
                (Details)                                                        
96: R78         Income Taxes - Reconciliation of the beginning and  HTML     57K 
                ending amount of unrecognized tax benefits                       
                (Details)                                                        
97: R79         Shareholders' Equity - Distributable Profits        HTML     42K 
                (Details)                                                        
98: R80         Shareholders' Equity - Ordinary Shares (Details)    HTML     63K 
99: R81         Shareholders' Equity - Schedule of weighted         HTML     50K 
                average shares outstanding (Details)                             
100: R82         Shareholders' Equity - Components of Accumulated    HTML     88K  
                other comprehensive loss, net of related tax                     
                (Details)                                                        
101: R83         Employee Benefits - Schedule of expense recognized  HTML     49K  
                in Compensation and benefit in the Consolidated                  
                Statements of Income (Details)                                   
102: R84         Employee Benefits - Pension Plans Narrative         HTML     76K  
                (Details)                                                        
103: R85         Employee Benefits - Reconciliation of the changes   HTML    119K  
                in the benefit obligations and fair value of                     
                assets and a statement of the funded status                      
                (Details)                                                        
104: R86         Employee Benefits - Amounts recognized in the       HTML     66K  
                Consolidated Statements of Financial Position                    
                (Details)                                                        
105: R87         Employee Benefits - Amounts recognized in           HTML     56K  
                Accumulated other comprehensive loss that have not               
                yet been recognized (Details)                                    
106: R88         Employee Benefits - Components of net periodic      HTML     80K  
                benefit cost (Details)                                           
107: R89         Employee Benefits - Weighted-average assumptions    HTML     61K  
                used to determine future benefit obligations                     
                (Details)                                                        
108: R90         Employee Benefits - Weighted-average assumptions    HTML     65K  
                used to determine the net periodic benefit cost                  
                (Details)                                                        
109: R91         Employee Benefits - Expected Return on Plan Assets  HTML     45K  
                Narrative (Details)                                              
110: R92         Employee Benefits - Schedule of Fair Value of U.S   HTML    107K  
                Plan Assets (Details)                                            
111: R93         Employee Benefits - Schedule of Fair Value of U.K.  HTML    110K  
                Plan Assets (Details)                                            
112: R94         Employee Benefits - Schedule of changes in Level 3  HTML     55K  
                fair value for U.K. Pension Plans (Details)                      
113: R95         Employee Benefits - Schedule of Fair Value of       HTML     97K  
                Other Plan Assets (Details)                                      
114: R96         Employee Benefits - Investment Policy and Strategy  HTML     56K  
                Narrative (Details)                                              
115: R97         Employee Benefits - Cash Flows Narrative (Details)  HTML     48K  
116: R98         Employee Benefits - Estimated Future Benefit        HTML     62K  
                Payments (Details)                                               
117: R99         Employee Benefits - Overview of the accumulated     HTML     57K  
                benefit obligation, fair value of plan assets,                   
                funded status and net amount recognized for U.S.                 
                and Canadian Other Post-Retirement Benefits                      
                (Details)                                                        
118: R100        Employee Benefits - Schedule of Other information   HTML     53K  
                related to Company's other post-retirement plan's                
                (Details)                                                        
119: R101        Employee Benefits - U.S. and Canadian Other         HTML     52K  
                Post-Retirement Benefits Narrative (Details)                     
120: R102        Share-Based Compensation Plans - Share-based        HTML     53K  
                compensation expense recognized in continuing                    
                operations (Details)                                             
121: R103        Share-Based Compensation Plans - Restricted Share   HTML     55K  
                Units Narrative (Details)                                        
122: R104        Share-Based Compensation Plans - Summary of the     HTML     64K  
                status of the Company's RSUs (Details)                           
123: R105        Share-Based Compensation Plans - Performance Share  HTML     58K  
                Awards Narrative (Details)                                       
124: R106        Share-Based Compensation Plans - Schedule of        HTML     50K  
                Performance-based plans (Details)                                
125: R107        Derivatives and Hedging - Narrative (Details)       HTML     64K  
126: R108        Derivatives and Hedging - Notional and fair values  HTML     63K  
                of derivative instruments (Details)                              
127: R109        Derivatives and Hedging - Schedule of amounts of    HTML     55K  
                derivative gains (losses) recognized in the                      
                Consolidated Financial Statements (Details)                      
128: R110        Fair Value Measurements and Financial Instruments   HTML     77K  
                - Schedule of assets and liabilities that are                    
                measured at fair value on a recurring basis                      
                (Details)                                                        
129: R111        Fair Value Measurements and Financial Instruments   HTML     42K  
                - Narrative (Details)                                            
130: R112        Fair Value Measurements and Financial Instruments   HTML     48K  
                - Schedule of financial instruments where the                    
                carrying amounts and fair values differ (Details)                
131: R113        Claims, Lawsuits, and Other Contingencies - Legal   HTML     95K  
                Narrative (Details)                                              
132: R114        Claims, Lawsuits, and Other Contingencies -         HTML     53K  
                Guarantees and Indemnifications Narrative                        
                (Details)                                                        
133: R115        Claims, Lawsuits, and Other Contingencies -         HTML     41K  
                Letters of Credit Narrative (Details)                            
134: R116        Claims, Lawsuits, and Other Contingencies -         HTML     41K  
                Premium Payments (Details)                                       
135: R117        Segment Information - Narrative (Details)           HTML     44K  
136: R118        Segment Information - Schedule of consolidated      HTML     55K  
                non-current assets by geographic area (Details)                  
139: XML         IDEA XML File -- Filing Summary                      XML    261K  
137: XML         XBRL Instance -- aon-20211231_htm                    XML   6.02M  
138: EXCEL       IDEA Workbook of Financial Reports                  XLSX    190K  
15: EX-101.CAL  XBRL Calculations -- aon-20211231_cal                XML    402K 
16: EX-101.DEF  XBRL Definitions -- aon-20211231_def                 XML   1.26M 
17: EX-101.LAB  XBRL Labels -- aon-20211231_lab                      XML   2.77M 
18: EX-101.PRE  XBRL Presentations -- aon-20211231_pre               XML   1.91M 
14: EX-101.SCH  XBRL Schema -- aon-20211231                          XSD    307K 
140: JSON        XBRL Instance as JSON Data -- MetaLinks              679±  1.00M  
141: ZIP         XBRL Zipped Folder -- 0001628280-22-003180-xbrl      Zip    703K

‘EX-101.LAB’   —   XBRL Labels — aon-20211231_lab

This Exhibit is an XBRL XML File.

                                                                                                                                                                                
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<!-- XBRL Document Created with Wdesk from Workiva -->
<!-- Copyright 2022 Workiva -->
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<link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
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<link:label id="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) </link:label>
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<link:label id="lab_us-gaap_LeaseholdImprovementsMember_8046213b-b2c5-47d2-9b7f-acf3584775c5_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseholdImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leasehold improvements </link:label>
<link:label id="lab_us-gaap_LeaseholdImprovementsMember_label_en-US" xlink:label="lab_us-gaap_LeaseholdImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leasehold Improvements [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseholdImprovementsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseholdImprovementsMember" xlink:to="lab_us-gaap_LeaseholdImprovementsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OperatingLeaseRightOfUseAssetAmortization_e4b8029a-8c47-4b0a-a09a-8279b1685fc3_terseLabel_en-US" xlink:label="lab_aon_OperatingLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating lease ROU asset expense </link:label>
<link:label id="lab_aon_OperatingLeaseRightOfUseAssetAmortization_label_en-US" xlink:label="lab_aon_OperatingLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Right Of Use Asset Amortization </link:label>
<link:label id="lab_aon_OperatingLeaseRightOfUseAssetAmortization_documentation_en-US" xlink:label="lab_aon_OperatingLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Right Of Use Asset Amortization </link:label>
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<link:label id="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease_e81c2004-0039-4df9-bb4f-db962e461360_terseLabel_en-US" xlink:label="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents and short term investments, period increase (decrease) </link:label>
<link:label id="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease_label_en-US" xlink:label="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash And Cash Equivalents And Short Term Investments, Period Increase (Decrease) </link:label>
<link:label id="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease_documentation_en-US" xlink:label="lab_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash And Cash Equivalents And Short Term Investments, Period Increase (Decrease) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease" xlink:href="aon-20211231.xsd#aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease"/>
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<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes_95851777-20c4-4976-adca-cc923c88bac3_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Adjustments to prior year tax requirements </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes"/>
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<link:label id="lab_us-gaap_DerivativeLiabilities_d41c7d39-837e-42f9-8a40-ee68216fe32a_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gross foreign exchange contracts </link:label>
<link:label id="lab_us-gaap_DerivativeLiabilities_label_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilities" xlink:to="lab_us-gaap_DerivativeLiabilities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DividendsCommonStockCash_eb8518bc-eeea-4057-bc77-876806e93634_negatedLabel_en-US" xlink:label="lab_us-gaap_DividendsCommonStockCash" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Dividends to shareholders </link:label>
<link:label id="lab_us-gaap_DividendsCommonStockCash_label_en-US" xlink:label="lab_us-gaap_DividendsCommonStockCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Dividends, Common Stock, Cash </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsCommonStockCash" xlink:to="lab_us-gaap_DividendsCommonStockCash" xlink:type="arc" order="1"/>
<link:label id="lab_dei_SecurityExchangeName_10940827-3192-437b-a627-6955781bf8f9_terseLabel_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Security Exchange Name </link:label>
<link:label id="lab_dei_SecurityExchangeName_label_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Security Exchange Name </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_SecurityExchangeName"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_SecurityExchangeName" xlink:to="lab_dei_SecurityExchangeName" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EMEAMember_17097aa9-b7a4-47fa-899c-6c307d059599_terseLabel_en-US" xlink:label="lab_us-gaap_EMEAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Europe, Middle East, & Africa </link:label>
<link:label id="lab_us-gaap_EMEAMember_label_en-US" xlink:label="lab_us-gaap_EMEAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> EMEA [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EMEAMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EMEAMember" xlink:to="lab_us-gaap_EMEAMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_1cf433d5-a6f2-4f2a-ac5c-cc9cb6f865b0_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Forfeited (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member_17e83193-b22d-4ccc-be62-7eb57770ca31_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 3.875% Senior Notes due 2025 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 3.875 Senior Notes Due 2025 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3875SeniorNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 3.875 Senior Notes Due 2025 </link:label>
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<link:label id="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_0b06f9d0-aea0-4ed0-9dfa-77afca48eea5_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating leases </link:label>
<link:label id="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Weighted Average Remaining Lease Term </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
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<link:label id="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_308f9b4b-e43b-4701-9de8-4c9991abb2a4_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Currency </link:label>
<link:label id="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Currency Transactions and Translations Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock"/>
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<link:label id="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_88788016-3157-4a29-bf47-3893a3308c36_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accrued benefit liability - current </link:label>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liability, Defined Benefit Plan, Current </link:label>
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<link:label id="lab_aon_A475SeniorNotesDueMay2045Member_fa78585a-611a-42ce-9695-5c6d9de8bfa1_terseLabel_en-US" xlink:label="lab_aon_A475SeniorNotesDueMay2045Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.75% Senior Notes due May 2045 </link:label>
<link:label id="lab_aon_A475SeniorNotesDueMay2045Member_label_en-US" xlink:label="lab_aon_A475SeniorNotesDueMay2045Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.75% Senior Notes Due May 2045 [Member] </link:label>
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<link:label id="lab_dei_EntityAddressCountry_e043efb2-c0b9-49d0-826a-4f65bd4ac252_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCountry" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Country </link:label>
<link:label id="lab_dei_EntityAddressCountry_label_en-US" xlink:label="lab_dei_EntityAddressCountry" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Country </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCountry" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCountry"/>
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<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Term Debt, Maturity, Year Two </link:label>
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<link:label id="lab_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_7125c04d-a5fd-495b-a2e5-60c18986113f_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current income taxes </link:label>
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<link:label id="lab_us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy_e0533f2f-7572-45d4-bbe3-ca4462ab9e1d_terseLabel_en-US" xlink:label="lab_us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Assets and Liabilities </link:label>
<link:label id="lab_us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy_label_en-US" xlink:label="lab_us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Transfers and Servicing of Financial Assets, Servicing of Financial Assets, Policy [Policy Text Block] </link:label>
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<link:label id="lab_us-gaap_SubsequentEventTypeDomain_ec0a412e-0d70-4cc1-af86-8dae2a1d484f_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event Type [Domain] </link:label>
<link:label id="lab_us-gaap_SubsequentEventTypeDomain_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event Type [Domain] </link:label>
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<link:label id="lab_us-gaap_ScheduleOfRepurchaseAgreements_fa99b77f-7ee2-43ad-be81-f50f3a56cf6c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRepurchaseAgreements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Repurchase Agreements </link:label>
<link:label id="lab_us-gaap_ScheduleOfRepurchaseAgreements_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRepurchaseAgreements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Repurchase Agreements [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRepurchaseAgreements" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRepurchaseAgreements"/>
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<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionOne_fa826ccf-d1e6-447e-9421-f29004c68769_terseLabel_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionOne" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Damages sought option 1 </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionOne_label_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionOne" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option One </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionOne_documentation_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionOne" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option One </link:label>
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<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_f3ae4b04-c49e-4fd4-bcfd-81e6ddfe08a8_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other intangible assets </link:label>
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<link:label id="lab_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_30c00147-9bc4-42f6-9a05-a28721f9cfac_terseLabel_en-US" xlink:label="lab_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average useful life </link:label>
<link:label id="lab_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_label_en-US" xlink:label="lab_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Acquired Finite-lived Intangible Assets, Weighted Average Useful Life </link:label>
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<link:label id="lab_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_34f8c95b-bfcb-4c03-8e5b-75fa30cf0fa1_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Remaining authorized repurchase amount </link:label>
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<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions_7e0d536b-f15f-47e5-a0af-54e63699853c_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additions based on tax positions related to the current year </link:label>
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<link:label id="lab_us-gaap_DeferredTaxAssetsLiabilitiesNet_b5e09f03-1456-4d5a-9fde-3e945b7c3e26_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net deferred tax asset </link:label>
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<link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_c74cf8b7-5a47-4a3f-88ff-aef8d5004e00_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Antidilutive securities excluded from computation of earnings per share (in shares) </link:label>
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<link:label id="lab_aon_NumberOfCreditFacilities_942da6f1-057d-41ac-9a4a-f88ae4f14c28_terseLabel_en-US" xlink:label="lab_aon_NumberOfCreditFacilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of credit facilities </link:label>
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<link:label id="lab_aon_NumberOfCreditFacilities_documentation_en-US" xlink:label="lab_aon_NumberOfCreditFacilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number Of Credit Facilities </link:label>
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<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NumberOfCreditFacilities" xlink:to="lab_aon_NumberOfCreditFacilities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EquitySecuritiesByIndustryAxis_aa72e6a2-0729-4e49-88db-f729e0870a19_terseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesByIndustryAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Industry Sector [Axis] </link:label>
<link:label id="lab_us-gaap_EquitySecuritiesByIndustryAxis_label_en-US" xlink:label="lab_us-gaap_EquitySecuritiesByIndustryAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Industry Sector [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesByIndustryAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesByIndustryAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquitySecuritiesByIndustryAxis" xlink:to="lab_us-gaap_EquitySecuritiesByIndustryAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock_5c932ef3-8229-4ec5-9898-661c700efafc_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in the Level 3 Fair-Value Category </link:label>
<link:label id="lab_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfEffectOfSignificantUnobservableInputsChangesInPlanAssetsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsNet_b1cd101f-4968-4b33-88b9-28d7c5424f5e_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsNet_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Net of Valuation Allowance </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsNet" xlink:to="lab_us-gaap_DeferredTaxAssetsNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination and Asset Acquisition [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationAndAssetAcquisitionAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:to="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessAcquisitionAxis_1f469d7b-1e2e-40ba-b0c2-a4a281135dc9_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition [Axis] </link:label>
<link:label id="lab_us-gaap_BusinessAcquisitionAxis_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionAxis" xlink:to="lab_us-gaap_BusinessAcquisitionAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CashFlowHedgingMember_c966707e-9305-4037-b708-88e747cc1cbf_terseLabel_en-US" xlink:label="lab_us-gaap_CashFlowHedgingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Flow Hedging </link:label>
<link:label id="lab_us-gaap_CashFlowHedgingMember_label_en-US" xlink:label="lab_us-gaap_CashFlowHedgingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Flow Hedging [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashFlowHedgingMember" xlink:to="lab_us-gaap_CashFlowHedgingMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bf04b7ca-e17e-4817-8988-f214a1d844b8_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Award Type [Domain] </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Award Type [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="1"/>
<link:label id="lab_dei_LocalPhoneNumber_215ecbc8-974e-4000-b9a7-1898c760cd19_terseLabel_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Local Phone Number </link:label>
<link:label id="lab_dei_LocalPhoneNumber_label_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Local Phone Number </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LocalPhoneNumber"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_LocalPhoneNumber" xlink:to="lab_dei_LocalPhoneNumber" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_44472350-08ee-4ea8-8e3a-024c52769e65_terseLabel_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor obligations, current carrying value </link:label>
<link:label id="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_label_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Current Carrying Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:to="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_d0397a26-d8d1-49a3-b819-9f2108369fcb_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization of net actuarial loss </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Amortization of Gain (Loss) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:to="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLossCarryforwardsLineItems_4cd88c4d-8aeb-471f-964e-fcfec79d1f5b_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Loss Carryforwards [Line Items] </link:label>
<link:label id="lab_us-gaap_OperatingLossCarryforwardsLineItems_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Loss Carryforwards [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems" xlink:to="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A280SeniorNotesDueMay2030Member_5307e111-11e4-46f1-b008-aa805aa5f3e2_terseLabel_en-US" xlink:label="lab_aon_A280SeniorNotesDueMay2030Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes due May 2030 </link:label>
<link:label id="lab_aon_A280SeniorNotesDueMay2030Member_label_en-US" xlink:label="lab_aon_A280SeniorNotesDueMay2030Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes Due May 2030 [Member] </link:label>
<link:label id="lab_aon_A280SeniorNotesDueMay2030Member_documentation_en-US" xlink:label="lab_aon_A280SeniorNotesDueMay2030Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes Due May 2030 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A280SeniorNotesDueMay2030Member" xlink:href="aon-20211231.xsd#aon_A280SeniorNotesDueMay2030Member"/>
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<link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock_2176f9f7-9ca6-4421-8269-0e651e08a5d7_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill and Intangible Assets </link:label>
<link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill and Intangible Assets, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_cf0a485c-156e-472e-aba9-36c04ba1d765_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> New Accounting Pronouncements or Change in Accounting Principle [Line Items] </link:label>
<link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_label_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> New Accounting Pronouncements or Change in Accounting Principle [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:to="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_91654ec2-df89-4345-a5ad-cfd3cd253365_negatedLabel_en-US" xlink:label="lab_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Dividends paid to noncontrolling interests on subsidiary common stock </link:label>
<link:label id="lab_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_label_en-US" xlink:label="lab_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
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<link:label id="lab_us-gaap_LossContingencyDamagesAwardedValue_b39e781c-7c4e-45c8-a1b7-16119f842dea_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyDamagesAwardedValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Damages awarded </link:label>
<link:label id="lab_us-gaap_LossContingencyDamagesAwardedValue_label_en-US" xlink:label="lab_us-gaap_LossContingencyDamagesAwardedValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency, Damages Awarded, Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyDamagesAwardedValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyDamagesAwardedValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyDamagesAwardedValue" xlink:to="lab_us-gaap_LossContingencyDamagesAwardedValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_05661b72-e253-4cec-959d-65f95b6f151f_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:to="lab_us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RetainedEarningsMember_30805ec6-0eaf-4409-8ad5-649f66ca3060_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retained Earnings (Accumulated Deficit) </link:label>
<link:label id="lab_us-gaap_RetainedEarningsMember_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retained Earnings [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsMember" xlink:to="lab_us-gaap_RetainedEarningsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FiduciaryAssetsPremiumTrustBalances_5d217137-5823-4791-b888-c2cd995fa088_terseLabel_en-US" xlink:label="lab_aon_FiduciaryAssetsPremiumTrustBalances" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Premium trust balances </link:label>
<link:label id="lab_aon_FiduciaryAssetsPremiumTrustBalances_label_en-US" xlink:label="lab_aon_FiduciaryAssetsPremiumTrustBalances" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Assets Premium Trust Balances </link:label>
<link:label id="lab_aon_FiduciaryAssetsPremiumTrustBalances_documentation_en-US" xlink:label="lab_aon_FiduciaryAssetsPremiumTrustBalances" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents premium trust balances for premiums collected from insureds but not yet remitted to insurance companies. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FiduciaryAssetsPremiumTrustBalances" xlink:href="aon-20211231.xsd#aon_FiduciaryAssetsPremiumTrustBalances"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FiduciaryAssetsPremiumTrustBalances" xlink:to="lab_aon_FiduciaryAssetsPremiumTrustBalances" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_20eb49e3-8976-4da4-8006-47ee3ca1c290_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Instruments and Hedging Activities Disclosure [Abstract] </link:label>
<link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Instruments and Hedging Activities Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_a228c7df-4923-4203-98f9-b4aa8ac30311_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed Assets, net [Line Items] </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityWellKnownSeasonedIssuer_2b4e1c13-c93e-4156-8201-511d5aa12962_terseLabel_en-US" xlink:label="lab_dei_EntityWellKnownSeasonedIssuer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Well-known Seasoned Issuer </link:label>
<link:label id="lab_dei_EntityWellKnownSeasonedIssuer_label_en-US" xlink:label="lab_dei_EntityWellKnownSeasonedIssuer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Well-known Seasoned Issuer </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityWellKnownSeasonedIssuer"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityWellKnownSeasonedIssuer" xlink:to="lab_dei_EntityWellKnownSeasonedIssuer" xlink:type="arc" order="1"/>
<link:label id="lab_aon_RestrictedCashOperatingFunds_4830b6eb-76a8-4d52-81d1-38ca5d2b66b6_terseLabel_en-US" xlink:label="lab_aon_RestrictedCashOperatingFunds" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating funds required to be held by the Company in the U.K. </link:label>
<link:label id="lab_aon_RestrictedCashOperatingFunds_label_en-US" xlink:label="lab_aon_RestrictedCashOperatingFunds" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted Cash Operating Funds </link:label>
<link:label id="lab_aon_RestrictedCashOperatingFunds_documentation_en-US" xlink:label="lab_aon_RestrictedCashOperatingFunds" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents cash that is restricted for minimum operating fund requirements. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_RestrictedCashOperatingFunds" xlink:href="aon-20211231.xsd#aon_RestrictedCashOperatingFunds"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_RestrictedCashOperatingFunds" xlink:to="lab_aon_RestrictedCashOperatingFunds" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherLongTermInvestmentsMember_a92c061b-3123-4bb5-b2ad-265ba77adef8_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLongTermInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Investments </link:label>
<link:label id="lab_us-gaap_OtherLongTermInvestmentsMember_label_en-US" xlink:label="lab_us-gaap_OtherLongTermInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Long-term Investments [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLongTermInvestmentsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLongTermInvestmentsMember" xlink:to="lab_us-gaap_OtherLongTermInvestmentsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_0ff87c87-5466-4d9e-bce7-edcfce083165_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing cash flows for finance leases </link:label>
<link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_label_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Principal Payments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:to="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties_174b7e83-0299-4ad7-9782-ee1696053f08_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Estimated retirement benefits covered by insurance contract, impact amount </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties" xlink:to="lab_us-gaap_DefinedBenefitPlanEstimatedAmountOfPlanParticipantsFutureBenefitsCoveredByInsuranceContractsIssuedByEmployerOrRelatedParties" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CompensationRelatedCostsPolicyTextBlock_4b43de36-3609-4fa8-9f26-b366bfdc0347_terseLabel_en-US" xlink:label="lab_us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Expense </link:label>
<link:label id="lab_us-gaap_CompensationRelatedCostsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation Related Costs, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CompensationRelatedCostsPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:to="lab_us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EarningsPerShareBasic_8afeef88-bdef-40f1-b1d1-647d26145fb5_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Basic net income per share attributable to Aon shareholders (in dollars per share) </link:label>
<link:label id="lab_us-gaap_EarningsPerShareBasic_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Earnings Per Share, Basic </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasic" xlink:to="lab_us-gaap_EarningsPerShareBasic" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent_7f0cc65e-7483-4ff2-bcd0-c05c047cd33c_terseLabel_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-deductible termination fee </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent_label_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Termination Fee, Percent </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent_documentation_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Termination Fee, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:href="aon-20211231.xsd#aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:to="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTerminationFeePercent" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount_4bd65bdd-22b5-4323-9a35-eb45dc0e9b19_negatedTotalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Imputed interest </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Net Of Sublease Income, Undiscounted Excess Amount </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Net Of Sublease Income, Undiscounted Excess Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CustomerRelatedAndContractBasedMember_6bdc50bb-57fc-4779-b79d-66e0301ea143_terseLabel_en-US" xlink:label="lab_aon_CustomerRelatedAndContractBasedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Customer-related and contract-based </link:label>
<link:label id="lab_aon_CustomerRelatedAndContractBasedMember_label_en-US" xlink:label="lab_aon_CustomerRelatedAndContractBasedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Customer Related and Contract Based [Member] </link:label>
<link:label id="lab_aon_CustomerRelatedAndContractBasedMember_documentation_en-US" xlink:label="lab_aon_CustomerRelatedAndContractBasedMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents finite-lived intangible assets such as client lists and non-compete agreements. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CustomerRelatedAndContractBasedMember" xlink:href="aon-20211231.xsd#aon_CustomerRelatedAndContractBasedMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CustomerRelatedAndContractBasedMember" xlink:to="lab_aon_CustomerRelatedAndContractBasedMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_e48c5c5e-589b-4e28-a92b-ce5061abf86d_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contracts with Customers </link:label>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contract with Customer [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SubleaseIncome_85d61d1e-8a60-43dc-8e8e-415bdbab14fe_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_SubleaseIncome" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Sublease income </link:label>
<link:label id="lab_us-gaap_SubleaseIncome_label_en-US" xlink:label="lab_us-gaap_SubleaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Sublease Income </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubleaseIncome"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubleaseIncome" xlink:to="lab_us-gaap_SubleaseIncome" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_3f213953-c9e4-4224-bd92-73bc42ddf206_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue, Initial Application Period Cumulative Effect Transition [Line Items] </link:label>
<link:label id="lab_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_label_en-US" xlink:label="lab_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue, Initial Application Period Cumulative Effect Transition [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:to="lab_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RestrictedCashAndInvestmentsCurrent_7f9408dd-8568-412c-88ed-6cdbda94e9ef_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted cash and investments, current </link:label>
<link:label id="lab_us-gaap_RestrictedCashAndInvestmentsCurrent_label_en-US" xlink:label="lab_us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted Cash and Investments, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndInvestmentsCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:to="lab_us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_aa2553b0-7e46-440c-9e5c-d7ad11595f11_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-vested at beginning of period (in shares) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c49ed1b7-c6cb-4c55-a717-5483e864442b_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-vested at end of period (in shares) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member_b86b4b1d-b70e-4b24-8689-98ef730bf30f_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 2.875% Senior Notes due 2026 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.875 Senior Notes Due 2026 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.875 Senior Notes Due 2026 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:to="lab_aon_GuaranteesOfAonPlcs2875SeniorNotesDue2026Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_80b80b8b-d3c8-48f6-ad71-1f843ab82a03_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Term Debt, Maturity, Year One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock_029cd39c-173c-4ce2-8f18-2aa6dee853fc_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Disclosure on Geographic Areas of Fixed Assets and Operating Lease Right-of-Use Asset </link:label>
<link:label id="lab_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock" xlink:to="lab_us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_WealthSolutionsMember_a6688829-e170-4794-a98e-5a75ff162300_terseLabel_en-US" xlink:label="lab_aon_WealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Wealth Solutions </link:label>
<link:label id="lab_aon_WealthSolutionsMember_label_en-US" xlink:label="lab_aon_WealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Wealth Solutions [Member] </link:label>
<link:label id="lab_aon_WealthSolutionsMember_documentation_en-US" xlink:label="lab_aon_WealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Wealth Solutions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_WealthSolutionsMember" xlink:href="aon-20211231.xsd#aon_WealthSolutionsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_WealthSolutionsMember" xlink:to="lab_aon_WealthSolutionsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember_6faac816-fe60-4e1e-a5ac-6bd8cc47eae1_terseLabel_en-US" xlink:label="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> European Program </link:label>
<link:label id="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember_label_en-US" xlink:label="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> European Multi Currency Commercial Paper Program [Member] </link:label>
<link:label id="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember_documentation_en-US" xlink:label="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> European Multi Currency Commercial Paper Program </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:href="aon-20211231.xsd#aon_EuropeanMultiCurrencyCommercialPaperProgramMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:to="lab_aon_EuropeanMultiCurrencyCommercialPaperProgramMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CapitalizedContractCostNet_f750b5c8-4420-4757-8084-9a03f2c30703_periodStartLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostNet" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at beginning of period </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostNet_9bd1d76c-92f0-4c25-9ca4-1745cb53a92f_periodEndLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostNet" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at end of period </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostNet_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalizedContractCostNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostNet" xlink:to="lab_us-gaap_CapitalizedContractCostNet" xlink:type="arc" order="1"/>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_e6245b72-f1a1-4127-8a27-a692d159442d_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption, Adjustment </link:label>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_label_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption, Adjustment [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:to="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract_a5e05450-633f-4ee5-8b78-fdd2faa05491_terseLabel_en-US" xlink:label="lab_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value of financial instrument </link:label>
<link:label id="lab_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract_label_en-US" xlink:label="lab_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial Instruments, Owned, at Fair Value [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract" xlink:to="lab_us-gaap_FinancialInstrumentsOwnedAtFairValueAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EquityInvestmentsPooledFundsMember_e2693b07-e7be-41b3-a27a-dd8cdcd509ca_terseLabel_en-US" xlink:label="lab_aon_EquityInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity investments, Pooled funds </link:label>
<link:label id="lab_aon_EquityInvestmentsPooledFundsMember_label_en-US" xlink:label="lab_aon_EquityInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Investments, Pooled Funds [Member] </link:label>
<link:label id="lab_aon_EquityInvestmentsPooledFundsMember_documentation_en-US" xlink:label="lab_aon_EquityInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Investments, Pooled Funds [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EquityInvestmentsPooledFundsMember" xlink:href="aon-20211231.xsd#aon_EquityInvestmentsPooledFundsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EquityInvestmentsPooledFundsMember" xlink:to="lab_aon_EquityInvestmentsPooledFundsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_a93aa7c1-d4f1-40f8-a0cc-0f82d7aa5641_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Prepaid pension </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets for Plan Benefits, Defined Benefit Plan </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:to="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommercialPaperMember_f1259758-3497-421b-af45-181aefb5cb7f_terseLabel_en-US" xlink:label="lab_us-gaap_CommercialPaperMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial paper </link:label>
<link:label id="lab_us-gaap_CommercialPaperMember_label_en-US" xlink:label="lab_us-gaap_CommercialPaperMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial Paper [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommercialPaperMember" xlink:to="lab_us-gaap_CommercialPaperMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxLiabilities_9eea6107-0726-491f-93f7-0087304453d6_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilities_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilities" xlink:to="lab_us-gaap_DeferredTaxLiabilities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_dacc58b8-7420-4958-ab0d-39deb13535e4_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity interest in acquiree, percentage </link:label>
<link:label id="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage" xlink:to="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeAsset_a009db20-7cc2-4696-b23d-0865c20f2961_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative assets </link:label>
<link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeAsset_label_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Asset, Fair Value, Gross Asset </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:to="lab_us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LossContingencyNumberOfPlaintiffs_c2c6b543-0c6c-4df5-bcc1-37d1613245b6_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyNumberOfPlaintiffs" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss contingency, number of plaintiffs </link:label>
<link:label id="lab_us-gaap_LossContingencyNumberOfPlaintiffs_label_en-US" xlink:label="lab_us-gaap_LossContingencyNumberOfPlaintiffs" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency, Number of Plaintiffs </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNumberOfPlaintiffs" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNumberOfPlaintiffs"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyNumberOfPlaintiffs" xlink:to="lab_us-gaap_LossContingencyNumberOfPlaintiffs" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ChristchurchCityCouncilMember_d7a49374-528b-4fb3-ae52-76b768caa4a4_terseLabel_en-US" xlink:label="lab_aon_ChristchurchCityCouncilMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Christchurch City Council </link:label>
<link:label id="lab_aon_ChristchurchCityCouncilMember_label_en-US" xlink:label="lab_aon_ChristchurchCityCouncilMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Christchurch City Council [Member] </link:label>
<link:label id="lab_aon_ChristchurchCityCouncilMember_documentation_en-US" xlink:label="lab_aon_ChristchurchCityCouncilMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Christchurch City Council [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ChristchurchCityCouncilMember" xlink:href="aon-20211231.xsd#aon_ChristchurchCityCouncilMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ChristchurchCityCouncilMember" xlink:to="lab_aon_ChristchurchCityCouncilMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_be9df32d-3bf1-46da-9d67-79334c9cabe0_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (loss) recognized in Accumulated other comprehensive loss </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:type="arc" order="1"/>
<link:label id="lab_aon_PaymentForDebtTerminationFee_87242acc-ad23-4392-8aca-8aaf95e1a10b_terseLabel_en-US" xlink:label="lab_aon_PaymentForDebtTerminationFee" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payment of termination fee </link:label>
<link:label id="lab_aon_PaymentForDebtTerminationFee_label_en-US" xlink:label="lab_aon_PaymentForDebtTerminationFee" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payment For Debt Termination Fee </link:label>
<link:label id="lab_aon_PaymentForDebtTerminationFee_documentation_en-US" xlink:label="lab_aon_PaymentForDebtTerminationFee" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payment For Debt Termination Fee </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_PaymentForDebtTerminationFee" xlink:href="aon-20211231.xsd#aon_PaymentForDebtTerminationFee"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_PaymentForDebtTerminationFee" xlink:to="lab_aon_PaymentForDebtTerminationFee" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityVoluntaryFilers_1e08de5b-263b-4577-8f35-5bdea58fa58b_terseLabel_en-US" xlink:label="lab_dei_EntityVoluntaryFilers" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Voluntary Filers </link:label>
<link:label id="lab_dei_EntityVoluntaryFilers_label_en-US" xlink:label="lab_dei_EntityVoluntaryFilers" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Voluntary Filers </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityVoluntaryFilers"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityVoluntaryFilers" xlink:to="lab_dei_EntityVoluntaryFilers" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PlanAssetCategoriesDomain_1d85ed77-6234-4b96-885c-316ac69edc05_terseLabel_en-US" xlink:label="lab_us-gaap_PlanAssetCategoriesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Category [Domain] </link:label>
<link:label id="lab_us-gaap_PlanAssetCategoriesDomain_label_en-US" xlink:label="lab_us-gaap_PlanAssetCategoriesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Category [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanAssetCategoriesDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain" xlink:to="lab_us-gaap_PlanAssetCategoriesDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AssetsFairValueDisclosureAbstract_7f2e14ef-f904-42b9-af33-11b4e95f0017_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets </link:label>
<link:label id="lab_us-gaap_AssetsFairValueDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets, Fair Value Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract" xlink:to="lab_us-gaap_AssetsFairValueDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PlanNameAxis_3e4d62b0-a069-4e02-870e-9a9f426f02be_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plan Name [Axis] </link:label>
<link:label id="lab_us-gaap_PlanNameAxis_label_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plan Name [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebt_2c6547d1-a54c-4a2e-b947-07bdde5728a8_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total Debt </link:label>
<link:label id="lab_us-gaap_LongTermDebt_label_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="lab_us-gaap_LongTermDebt" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsForRepurchaseOfEquity_1d92914a-46c9-473c-baba-177119de20cd_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfEquity" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share repurchase </link:label>
<link:label id="lab_us-gaap_PaymentsForRepurchaseOfEquity_label_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments for Repurchase of Equity </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForRepurchaseOfEquity" xlink:to="lab_us-gaap_PaymentsForRepurchaseOfEquity" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueInputsLevel1Member_99c93b50-9750-4886-81f9-b6efd2751900_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Quoted Prices in Active Markets for Identical Assets (Level 1) </link:label>
<link:label id="lab_us-gaap_FairValueInputsLevel1Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Inputs, Level 1 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel1Member" xlink:to="lab_us-gaap_FairValueInputsLevel1Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_6176c575-c330-4399-813c-1f635f0d1fb2_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash flows from investing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Investing Activities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_4ef81927-a91f-4b7f-bf48-c13e3892118d_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Disclosure [Abstract] </link:label>
<link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract" xlink:to="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A290SeniorNotesDueAugust2051Member_e78deab8-3785-4c55-a8b7-d7aa35ff312b_terseLabel_en-US" xlink:label="lab_aon_A290SeniorNotesDueAugust2051Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.90% Senior Notes due August 2051 </link:label>
<link:label id="lab_aon_A290SeniorNotesDueAugust2051Member_label_en-US" xlink:label="lab_aon_A290SeniorNotesDueAugust2051Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.90% Senior Notes Due August 2051 [Member] </link:label>
<link:label id="lab_aon_A290SeniorNotesDueAugust2051Member_documentation_en-US" xlink:label="lab_aon_A290SeniorNotesDueAugust2051Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.90% Senior Notes Due August 2051 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A290SeniorNotesDueAugust2051Member" xlink:href="aon-20211231.xsd#aon_A290SeniorNotesDueAugust2051Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A290SeniorNotesDueAugust2051Member" xlink:to="lab_aon_A290SeniorNotesDueAugust2051Member" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntitySmallBusiness_ba15a7a1-e3cd-4fba-81d5-22e4c19043e5_terseLabel_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Small Business </link:label>
<link:label id="lab_dei_EntitySmallBusiness_label_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Small Business </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitySmallBusiness"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntitySmallBusiness" xlink:to="lab_dei_EntitySmallBusiness" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_64ca58b0-a436-44a2-8b3f-233524d7da11_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Leases </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, Payment, Due [Abstract] </link:label>
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<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_b32ac72f-33d3-4119-8926-578327f8274d_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additions for tax positions of prior years </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions"/>
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<link:label id="lab_aon_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAbstract_84979b0f-9b3d-405b-99fc-4e6c78fd5525_terseLabel_en-US" xlink:label="lab_aon_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (loss) before income taxes: </link:label>
<link:label id="lab_aon_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAbstract_label_en-US" xlink:label="lab_aon_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (Loss) from Continuing Operations before Income Taxes [Abstract] </link:label>
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<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour_f8190c74-5816-48ab-b3da-9900857fc866_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2025 </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Four </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Four </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFour"/>
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<link:label id="lab_aon_CytelligenceIncMember_e4a7ebee-71c1-4410-863d-eb2dd1f057e8_terseLabel_en-US" xlink:label="lab_aon_CytelligenceIncMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cytelligence Inc. </link:label>
<link:label id="lab_aon_CytelligenceIncMember_label_en-US" xlink:label="lab_aon_CytelligenceIncMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cytelligence Inc. [Member] </link:label>
<link:label id="lab_aon_CytelligenceIncMember_documentation_en-US" xlink:label="lab_aon_CytelligenceIncMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cytelligence Inc. </link:label>
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<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems_d85e33e3-201b-4d38-a209-53413c7a8555_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets [Line Items] </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PendingLitigationMember_7d23b896-b351-44cd-a6b4-77954fd1d949_terseLabel_en-US" xlink:label="lab_us-gaap_PendingLitigationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pending Litigation </link:label>
<link:label id="lab_us-gaap_PendingLitigationMember_label_en-US" xlink:label="lab_us-gaap_PendingLitigationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pending Litigation [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PendingLitigationMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PendingLitigationMember"/>
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<link:label id="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock_1f0677fb-3384-4750-824b-314947001529_terseLabel_en-US" xlink:label="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Allowance for Doubtful Accounts </link:label>
<link:label id="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock_label_en-US" xlink:label="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Accounts, Notes, Loans and Financing Receivable Allowance for Doubtful Accounts [Table Text Block] </link:label>
<link:label id="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock_documentation_en-US" xlink:label="lab_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Accounts, Notes, Loans and Financing Receivable Allowance for Doubtful Accounts [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" xlink:href="aon-20211231.xsd#aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock"/>
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<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAmendments_e9a1f5e9-9185-43dd-aa73-2f927cdc19f6_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAmendments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plan amendment </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAmendments_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAmendments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAmendments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAmendments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAmendments" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAmendments" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A3.50NotesdueJune2024Member_ad6d9857-651d-4d84-a716-9b7663ffde58_terseLabel_en-US" xlink:label="lab_aon_A3.50NotesdueJune2024Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.50% Senior Notes due June 2024 </link:label>
<link:label id="lab_aon_A3.50NotesdueJune2024Member_label_en-US" xlink:label="lab_aon_A3.50NotesdueJune2024Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.50% Notes due June 2024 [Member] </link:label>
<link:label id="lab_aon_A3.50NotesdueJune2024Member_documentation_en-US" xlink:label="lab_aon_A3.50NotesdueJune2024Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.50% Notes due June 2024 [Member] </link:label>
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<link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8fde20fd-643d-413b-ae8e-c7b8eca22074_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities and equity </link:label>
<link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities and Equity [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
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<link:label id="lab_aon_LeadershipPerformancePlanCycle20162018Member_5f0e1f0c-9f96-4ab5-9bc1-45b3f1fda2d9_terseLabel_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20162018Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2016-2018 </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20162018Member_label_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20162018Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2016-2018 [Member] </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20162018Member_documentation_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20162018Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2016-2018 </link:label>
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<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_21b1d68b-bb13-497a-b468-625680973723_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized tax benefits that would impact effective tax rate </link:label>
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<link:label id="lab_us-gaap_HedgingRelationshipDomain_5bd5a4a6-dc7a-4f6a-a51d-4baa9e0a58fb_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingRelationshipDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Relationship [Domain] </link:label>
<link:label id="lab_us-gaap_HedgingRelationshipDomain_label_en-US" xlink:label="lab_us-gaap_HedgingRelationshipDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Relationship [Domain] </link:label>
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<link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_f1bc7094-84fe-4798-b3f8-22efd7eccf32_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts payable and accrued liabilities </link:label>
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<link:label id="lab_dei_EntityInteractiveDataCurrent_8ec46754-e75f-4dc4-a3e9-99f66460e5fe_terseLabel_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Interactive Data Current </link:label>
<link:label id="lab_dei_EntityInteractiveDataCurrent_label_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Interactive Data Current </link:label>
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<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_07c9d63e-13f1-477a-b949-974032398902_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Thereafter </link:label>
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<link:label id="lab_us-gaap_BalanceSheetLocationDomain_label_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance Sheet Location [Domain] </link:label>
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<link:label id="lab_us-gaap_UnrecognizedTaxBenefits_22c7af34-8f1f-4b8e-81be-8a297487ee99_periodStartLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefits" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the beginning of the period </link:label>
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<link:label id="lab_us-gaap_DeferredTaxAssetsGross_46e82ca0-1168-48c9-ae38-3901737231a3_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsGross_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Gross </link:label>
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<link:label id="lab_us-gaap_IncomeTaxAuthorityDomain_f26e7baf-b029-4db5-8c5e-b2f4e6286ca8_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Domain] </link:label>
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<link:label id="lab_aon_CashPaidForLeasesAbstract_47de2dcb-c254-493e-83fb-75b6e225403e_terseLabel_en-US" xlink:label="lab_aon_CashPaidForLeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash paid for amounts included in the measurement of lease liabilities </link:label>
<link:label id="lab_aon_CashPaidForLeasesAbstract_label_en-US" xlink:label="lab_aon_CashPaidForLeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Paid For Leases [Abstract] </link:label>
<link:label id="lab_aon_CashPaidForLeasesAbstract_documentation_en-US" xlink:label="lab_aon_CashPaidForLeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Paid For Leases [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CashPaidForLeasesAbstract" xlink:href="aon-20211231.xsd#aon_CashPaidForLeasesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CashPaidForLeasesAbstract" xlink:to="lab_aon_CashPaidForLeasesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LossContingencyDamagesSoughtValue_05214b3a-464a-424e-83c6-6ce11eef131c_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyDamagesSoughtValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Value of damages sought </link:label>
<link:label id="lab_us-gaap_LossContingencyDamagesSoughtValue_label_en-US" xlink:label="lab_us-gaap_LossContingencyDamagesSoughtValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency, Damages Sought, Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyDamagesSoughtValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyDamagesSoughtValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyDamagesSoughtValue" xlink:to="lab_us-gaap_LossContingencyDamagesSoughtValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains_7259de57-cd23-4617-b638-0ccd6e60ed8b_negatedLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrealized foreign exchange gains </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Unrealized Currency Transaction Gains </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesUnrealizedCurrencyTransactionGains" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_0edeb0ff-fe57-470f-b804-a609d1d62b6a_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts reclassified from accumulated other comprehensive income (loss), net </link:label>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_label_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:to="lab_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_2d517ef8-40fb-434a-aa20-fca1e4c83d64_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax assets </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_aad9e836-fcc4-4622-884c-882886aa5cfe_verboseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax assets — non-current </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Tax Assets, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:type="arc" order="1"/>
<link:label id="lab_country_GB_2de5112d-9871-4a6e-8aa9-72cc73c32114_terseLabel_en-US" xlink:label="lab_country_GB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.K. </link:label>
<link:label id="lab_country_GB_6e088438-857f-4932-910b-541c698c8d69_verboseLabel_en-US" xlink:label="lab_country_GB" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> United Kingdom </link:label>
<link:label id="lab_country_GB_label_en-US" xlink:label="lab_country_GB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> UNITED KINGDOM </link:label>
<link:loc xlink:type="locator" xlink:label="loc_country_GB" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_GB"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_GB" xlink:to="lab_country_GB" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LiabilitiesCurrentAbstract_3e0e388f-7ae5-44a0-bb04-d402c47ba132_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current liabilities </link:label>
<link:label id="lab_us-gaap_LiabilitiesCurrentAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities, Current [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="lab_us-gaap_LiabilitiesCurrentAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_srt_RestatementAxis_79bc7b6e-9e04-4847-ac23-819d5389a2bc_terseLabel_en-US" xlink:label="lab_srt_RestatementAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period [Axis] </link:label>
<link:label id="lab_srt_RestatementAxis_label_en-US" xlink:label="lab_srt_RestatementAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RestatementAxis" xlink:to="lab_srt_RestatementAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EquitySecuritiesMember_123a015b-3d62-40e3-be79-86fa70f6b534_verboseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity investments </link:label>
<link:label id="lab_us-gaap_EquitySecuritiesMember_label_en-US" xlink:label="lab_us-gaap_EquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Securities [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquitySecuritiesMember" xlink:to="lab_us-gaap_EquitySecuritiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_213e619a-7224-4761-a5d0-e77c1add07a7_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liability recorded for interest and penalties </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:to="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccountingPoliciesAbstract_e000e7a1-50e5-4ed4-87a0-c1a31de4344a_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounting Policies [Abstract] </link:label>
<link:label id="lab_us-gaap_AccountingPoliciesAbstract_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounting Policies [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingPoliciesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_bbb8a116-5f70-4d0e-8d5d-13aa590b1538_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2025 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_8a7b085d-e8e7-48c8-8d8a-49c2d8beb99c_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected future benefit payments 2025 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, Year Four </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_ee964f88-3cbe-4454-9288-10d0d2904d1d_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative, by Nature [Axis] </link:label>
<link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Instrument [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:to="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RetirementPlanSponsorLocationAxis_20af9ff5-3b12-4776-a82f-cb411ce6d361_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Sponsor Location [Axis] </link:label>
<link:label id="lab_us-gaap_RetirementPlanSponsorLocationAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Sponsor Location [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanSponsorLocationAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis" xlink:to="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseLiability_272129b3-4d2a-4cee-aeb0-0cccf6df7cce_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Present value of lease liabilities </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiability" xlink:to="lab_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="1"/>
<link:label id="lab_dei_DocumentTransitionReport_42190e73-6533-45a2-9dc0-e10f770fe2e0_terseLabel_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Transition Report </link:label>
<link:label id="lab_dei_DocumentTransitionReport_label_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Transition Report </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentTransitionReport"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentTransitionReport" xlink:to="lab_dei_DocumentTransitionReport" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_2f8d8344-b1d2-4862-9d5b-db76f86c4fd7_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:to="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear_202692de-4d90-4c64-83fd-067ff7fb5105_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts in Accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost in next fiscal year </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockValue_cc89b642-e0e9-4826-ad14-01d5cf21faec_verboseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ordinary shares - $0.01 nominal value Authorized: 500.0 shares (issued: 2021 - 214.8; 2020 - 225.5) </link:label>
<link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock, Value, Issued </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockValue" xlink:to="lab_us-gaap_CommonStockValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EquityDerivativeMember_5724c2a3-6223-4edb-baf4-a89d9a761f48_terseLabel_en-US" xlink:label="lab_aon_EquityDerivativeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity derivatives </link:label>
<link:label id="lab_aon_EquityDerivativeMember_label_en-US" xlink:label="lab_aon_EquityDerivativeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Derivative [Member] </link:label>
<link:label id="lab_aon_EquityDerivativeMember_documentation_en-US" xlink:label="lab_aon_EquityDerivativeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the equity investments in equity derivatives. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EquityDerivativeMember" xlink:href="aon-20211231.xsd#aon_EquityDerivativeMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EquityDerivativeMember" xlink:to="lab_aon_EquityDerivativeMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_56badb65-c383-4f96-b21c-1cae364b25e3_verboseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average remaining amortization period (in years) </link:label>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_7e9e07db-6bc9-4fa7-affd-8b0a533757e0_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-vested at beginning of period (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_44cdcfb2-7a64-45ef-87a4-481e44b249c5_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-vested at end of period (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_fa6f48a3-ea16-455f-afd9-3d190de099c9_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease Commitments </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Leases [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested_25e0a242-2098-4ef9-8e22-d0a65e7d8a03_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Sale of businesses, net of cash and funds held on behalf of clients </link:label>
<link:label id="lab_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested_label_en-US" xlink:label="lab_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Proceeds from Divestiture of Businesses, Net of Cash Divested </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested" xlink:to="lab_us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock_48a4d783-29a3-4015-8835-675276b2b5dd_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Financial Instruments where the Carrying Amounts and Fair Values Differ </link:label>
<link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, by Balance Sheet Grouping [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:to="lab_us-gaap_FairValueByBalanceSheetGroupingTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization_43a478e1-d021-4467-9fd4-3fe87e0182a8_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization of leased assets </link:label>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Right-of-Use Asset, Amortization </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_a2bce581-7ee0-455b-82f5-5f2417662f34_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Funded status </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Funded (Unfunded) Status of Plan </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:to="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherInvestments_e3b54fdf-1672-4a15-9b0e-3dcf2df61bad_terseLabel_en-US" xlink:label="lab_us-gaap_OtherInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other investments </link:label>
<link:label id="lab_us-gaap_OtherInvestments_label_en-US" xlink:label="lab_us-gaap_OtherInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherInvestments" xlink:to="lab_us-gaap_OtherInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FurnitureFixturesAndEquipmentMember_e77239be-338e-4a89-8705-3efdcc92ae6e_terseLabel_en-US" xlink:label="lab_aon_FurnitureFixturesAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Furniture, fixtures and equipment </link:label>
<link:label id="lab_aon_FurnitureFixturesAndEquipmentMember_label_en-US" xlink:label="lab_aon_FurnitureFixturesAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Furniture, Fixtures and Equipment [Member] </link:label>
<link:label id="lab_aon_FurnitureFixturesAndEquipmentMember_documentation_en-US" xlink:label="lab_aon_FurnitureFixturesAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-lived, depreciable assets, commonly used in offices and stores. Tangible personal property, nonconsumable in nature, with finite lives used to produce goods and services. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FurnitureFixturesAndEquipmentMember" xlink:href="aon-20211231.xsd#aon_FurnitureFixturesAndEquipmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FurnitureFixturesAndEquipmentMember" xlink:to="lab_aon_FurnitureFixturesAndEquipmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_dei_IcfrAuditorAttestationFlag_2215c845-755f-4419-950f-d5bd4caf37bc_terseLabel_en-US" xlink:label="lab_dei_IcfrAuditorAttestationFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> ICFR Auditor Attestation Flag </link:label>
<link:label id="lab_dei_IcfrAuditorAttestationFlag_label_en-US" xlink:label="lab_dei_IcfrAuditorAttestationFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> ICFR Auditor Attestation Flag </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_IcfrAuditorAttestationFlag"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_IcfrAuditorAttestationFlag" xlink:to="lab_dei_IcfrAuditorAttestationFlag" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock_64e8650c-1235-4d88-a612-bd62b6421df3_terseLabel_en-US" xlink:label="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets And Liabilities Of Lessee </link:label>
<link:label id="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock_label_en-US" xlink:label="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets And Liabilities Of Lessee [Table Text Block] </link:label>
<link:label id="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock_documentation_en-US" xlink:label="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets And Liabilities Of Lessee [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:href="aon-20211231.xsd#aon_AssetsAndLiabilitiesOfLesseeTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:to="lab_aon_AssetsAndLiabilitiesOfLesseeTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CapitalLossCarryforwards_34744961-1c55-4dea-b90e-1b3e657283fb_terseLabel_en-US" xlink:label="lab_aon_CapitalLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capital loss carryforwards </link:label>
<link:label id="lab_aon_CapitalLossCarryforwards_label_en-US" xlink:label="lab_aon_CapitalLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capital Loss Carryforwards </link:label>
<link:label id="lab_aon_CapitalLossCarryforwards_documentation_en-US" xlink:label="lab_aon_CapitalLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The sum of domestic, foreign and state and local capital loss carryforwards, before tax effects, available to reduce future taxable income under enacted tax laws. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CapitalLossCarryforwards" xlink:href="aon-20211231.xsd#aon_CapitalLossCarryforwards"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CapitalLossCarryforwards" xlink:to="lab_aon_CapitalLossCarryforwards" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfOtherAssetsNoncurrentTextBlock_3d0e7314-4844-4e73-9b46-4b8a3d99bbc8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherAssetsNoncurrentTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Non-current Assets </link:label>
<link:label id="lab_us-gaap_ScheduleOfOtherAssetsNoncurrentTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherAssetsNoncurrentTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Assets, Noncurrent [Table Text Block] </link:label>
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<link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_2d09705a-c4b5-4b9b-adfb-05a948bbdbd5_terseLabel_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Dilutive effect of potentially issuable shares (in shares) </link:label>
<link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_label_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
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<link:label id="lab_us-gaap_StatementClassOfStockAxis_a3a14c97-9168-4058-842e-41a3c5fe11bb_terseLabel_en-US" xlink:label="lab_us-gaap_StatementClassOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Class of Stock [Axis] </link:label>
<link:label id="lab_us-gaap_StatementClassOfStockAxis_label_en-US" xlink:label="lab_us-gaap_StatementClassOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Class of Stock [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementClassOfStockAxis" xlink:to="lab_us-gaap_StatementClassOfStockAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_6a25a080-6fb9-43b5-baf9-fd4f626d2b4b_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expense Recognized for Defined Contribution Savings Plans, Included in Compensation and Benefits and Discontinued Operations in the Consolidated Statements of Income </link:label>
<link:label id="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Costs of Retirement Plans [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock"/>
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<link:label id="lab_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_54fbb130-2d2f-455b-8631-fa27b3c2188a_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension, other postretirement, and postemployment liabilities </link:label>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementAndPostemploymentBenefitPlansLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liability, Pension and Other Postretirement and Postemployment Benefits, Noncurrent </link:label>
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<link:label id="lab_us-gaap_SummaryOfIncomeTaxContingenciesTextBlock_ae40cb48-72dc-4e77-ba29-c615b593093c_terseLabel_en-US" xlink:label="lab_us-gaap_SummaryOfIncomeTaxContingenciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits </link:label>
<link:label id="lab_us-gaap_SummaryOfIncomeTaxContingenciesTextBlock_label_en-US" xlink:label="lab_us-gaap_SummaryOfIncomeTaxContingenciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Summary of Income Tax Contingencies [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SummaryOfIncomeTaxContingenciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SummaryOfIncomeTaxContingenciesTextBlock"/>
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<link:label id="lab_us-gaap_IncomeTaxAuthorityAxis_ccddf907-38cc-4da9-9e7a-5e057b74617f_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Axis] </link:label>
<link:label id="lab_us-gaap_IncomeTaxAuthorityAxis_label_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis" xlink:to="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:type="arc" order="1"/>
<link:label id="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod_6eecc2f6-eaa2-4830-b4d0-8b0c2687124d_terseLabel_en-US" xlink:label="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share repurchase authorization amount, increase during period </link:label>
<link:label id="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod_label_en-US" xlink:label="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stock Repurchase Program, Authorized Amount, Increase During Period </link:label>
<link:label id="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod_documentation_en-US" xlink:label="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stock Repurchase Program, Authorized Amount, Increase During Period </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:href="aon-20211231.xsd#aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:to="lab_aon_StockRepurchaseProgramAuthorizedAmountIncreaseDuringPeriod" xlink:type="arc" order="1"/>
<link:label id="lab_aon_TempoBusinessMember_c059d2ed-ffed-408a-96b9-12d7186fa016_terseLabel_en-US" xlink:label="lab_aon_TempoBusinessMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tempo Business </link:label>
<link:label id="lab_aon_TempoBusinessMember_label_en-US" xlink:label="lab_aon_TempoBusinessMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tempo Business [Member] </link:label>
<link:label id="lab_aon_TempoBusinessMember_documentation_en-US" xlink:label="lab_aon_TempoBusinessMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tempo Business [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_TempoBusinessMember" xlink:href="aon-20211231.xsd#aon_TempoBusinessMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_TempoBusinessMember" xlink:to="lab_aon_TempoBusinessMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeFinanceLeaseDiscountRate_d07ace65-b965-49aa-bda8-50810dbfe350_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance leases </link:label>
<link:label id="lab_us-gaap_LesseeFinanceLeaseDiscountRate_label_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Finance Lease, Discount Rate </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeFinanceLeaseDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeFinanceLeaseDiscountRate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeFinanceLeaseDiscountRate" xlink:to="lab_us-gaap_LesseeFinanceLeaseDiscountRate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_dac38381-27cf-4e09-9b43-01982a60a667_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tax benefit (expense) </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss) before Reclassifications, Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_940a637d-a4a4-47d5-bded-319ee5cd5106_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Thereafter </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, to be Paid, after Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive"/>
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<link:label id="lab_us-gaap_FixedIncomeInvestmentsMember_4d680c3f-eaea-4d4e-932a-04d2981b9579_terseLabel_en-US" xlink:label="lab_us-gaap_FixedIncomeInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed income investments </link:label>
<link:label id="lab_us-gaap_FixedIncomeInvestmentsMember_label_en-US" xlink:label="lab_us-gaap_FixedIncomeInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed Income Investments [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeInvestmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FixedIncomeInvestmentsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FixedIncomeInvestmentsMember" xlink:to="lab_us-gaap_FixedIncomeInvestmentsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockDividendsPerShareDeclared_ac439e27-26ec-4b49-993f-367afc9bf364_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockDividendsPerShareDeclared" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Dividends (in dollars per share) </link:label>
<link:label id="lab_us-gaap_CommonStockDividendsPerShareDeclared_label_en-US" xlink:label="lab_us-gaap_CommonStockDividendsPerShareDeclared" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock, Dividends, Per Share, Declared </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
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<link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b2b9e522-9841-443e-9099-ce97ae52721c_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total revenue </link:label>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contract with Customer, Excluding Assessed Tax </link:label>
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<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_47d5d250-869b-4235-91d2-671421e5adb2_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets acquired </link:label>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] </link:label>
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<link:label id="lab_us-gaap_PerformanceGuaranteeMember_659d5c63-99a2-46aa-9208-e82bcfb759f2_terseLabel_en-US" xlink:label="lab_us-gaap_PerformanceGuaranteeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Performance Guarantee </link:label>
<link:label id="lab_us-gaap_PerformanceGuaranteeMember_label_en-US" xlink:label="lab_us-gaap_PerformanceGuaranteeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Performance Guarantee [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceGuaranteeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PerformanceGuaranteeMember"/>
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<link:label id="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate_081cf6c6-314c-4253-9bab-b110bac1c7fd_terseLabel_en-US" xlink:label="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average interest rate of commercial paper outstanding </link:label>
<link:label id="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate_label_en-US" xlink:label="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short Term Debt, Average Outstanding Amount, Weighted Average Interest Rate </link:label>
<link:label id="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate_documentation_en-US" xlink:label="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reflects the calculation as of the balance sheet date of the average interest rate weighted by the average outstanding amount of short-term debt outstanding by type or by instrument at that time. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:href="aon-20211231.xsd#aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:to="lab_aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_66904d20-bc8f-484f-b224-11091017b517_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Hierarchy and NAV [Axis] </link:label>
<link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Hierarchy and NAV [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EquityAbstract_58f32e1f-5083-4a8e-bc53-f526ecb0ec44_terseLabel_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity [Abstract] </link:label>
<link:label id="lab_us-gaap_EquityAbstract_label_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityAbstract" xlink:to="lab_us-gaap_EquityAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CurrentLeaseLiabilitiesAbstract_f5aff902-8f89-4ab8-a172-0ab289f8292c_terseLabel_en-US" xlink:label="lab_aon_CurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current lease liabilities </link:label>
<link:label id="lab_aon_CurrentLeaseLiabilitiesAbstract_label_en-US" xlink:label="lab_aon_CurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Lease Liabilities [Abstract] </link:label>
<link:label id="lab_aon_CurrentLeaseLiabilitiesAbstract_documentation_en-US" xlink:label="lab_aon_CurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Lease Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CurrentLeaseLiabilitiesAbstract" xlink:href="aon-20211231.xsd#aon_CurrentLeaseLiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CurrentLeaseLiabilitiesAbstract" xlink:to="lab_aon_CurrentLeaseLiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_srt_ConsolidationItemsDomain_73b8f06f-2326-4ad9-b90b-33f7714ba3d9_terseLabel_en-US" xlink:label="lab_srt_ConsolidationItemsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consolidation Items [Domain] </link:label>
<link:label id="lab_srt_ConsolidationItemsDomain_label_en-US" xlink:label="lab_srt_ConsolidationItemsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consolidation Items [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidationItemsDomain" xlink:to="lab_srt_ConsolidationItemsDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLossCarryforwardsTable_d314f033-3424-4f9d-b054-c4955d0f7911_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Loss Carryforwards [Table] </link:label>
<link:label id="lab_us-gaap_OperatingLossCarryforwardsTable_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Loss Carryforwards [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable" xlink:to="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NotesPayableOtherPayablesMember_29a7a1e2-aa0e-4dd4-bda0-1895f0a9d57f_terseLabel_en-US" xlink:label="lab_us-gaap_NotesPayableOtherPayablesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_NotesPayableOtherPayablesMember_label_en-US" xlink:label="lab_us-gaap_NotesPayableOtherPayablesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Notes Payable, Other Payables [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NotesPayableOtherPayablesMember" xlink:to="lab_us-gaap_NotesPayableOtherPayablesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_664ecc72-de38-4ebb-9387-3705c193dcb5_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Segment Information </link:label>
<link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Segment Reporting Disclosure [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingDisclosureTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_a65f1a51-93a3-4f15-9cfb-38d4c45d54fb_totalLabel_en-US" xlink:label="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other comprehensive income (loss) before reclassifications, net </link:label>
<link:label id="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> OCI, before Reclassifications, Net of Tax, Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:to="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_d73f0949-e800-4450-a924-d128df1e916c_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance leases </link:label>
<link:label id="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Weighted Average Remaining Lease Term </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_MinorityInterestDecreaseFromRedemptions_d955d98d-0531-4f00-8120-c09f57a057c8_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net purchases of shares from noncontrolling interests </link:label>
<link:label id="lab_us-gaap_MinorityInterestDecreaseFromRedemptions_label_en-US" xlink:label="lab_us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:to="lab_us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f16cfe92-6d8c-4a48-ad26-a72e244b4825_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Property, Plant and Equipment [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff_17578f02-53b6-42ec-a8d3-1b2bc8cc7080_terseLabel_en-US" xlink:label="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Investment losses suffered by plaintiff </link:label>
<link:label id="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff_label_en-US" xlink:label="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Investment Losses Suffered By Plaintiff </link:label>
<link:label id="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff_documentation_en-US" xlink:label="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Investment Losses Suffered By Plaintiff </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:href="aon-20211231.xsd#aon_LossContingencyInvestmentLossesSufferedByPlaintiff"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:to="lab_aon_LossContingencyInvestmentLossesSufferedByPlaintiff" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_d51e83c4-96f5-487b-8cad-877d56100300_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Shareholders' Equity </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Stockholders' Equity [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
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<link:label id="lab_dei_DocumentFiscalYearFocus_06fc58c3-a0f3-45a1-8f41-39d1032ae7d5_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Fiscal Year Focus </link:label>
<link:label id="lab_dei_DocumentFiscalYearFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Fiscal Year Focus </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalYearFocus"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalYearFocus" xlink:to="lab_dei_DocumentFiscalYearFocus" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionThree_4cda568b-d8be-4de5-ada0-1ab658eb9917_terseLabel_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Damages sought option 3 </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionThree_label_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option Three </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionThree_documentation_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:href="aon-20211231.xsd#aon_LossContingencyDamagesSoughtValueOptionThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:to="lab_aon_LossContingencyDamagesSoughtValueOptionThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsToAcquireOtherInvestments_5b95dc20-4714-4c16-b5e4-f81d98fec7dd_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireOtherInvestments" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments for investments </link:label>
<link:label id="lab_us-gaap_PaymentsToAcquireOtherInvestments_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to Acquire Other Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireOtherInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireOtherInvestments" xlink:to="lab_us-gaap_PaymentsToAcquireOtherInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_558cf8a0-0a9d-4a8d-a0d3-45f9dc5a7fb4_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2027 - 2031 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FarmingtonAdministrativeServicesLLCMember_00e38569-7f33-4b7f-9ce1-e8ed8a915a1b_terseLabel_en-US" xlink:label="lab_aon_FarmingtonAdministrativeServicesLLCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Farmington Administrative Services LLC </link:label>
<link:label id="lab_aon_FarmingtonAdministrativeServicesLLCMember_label_en-US" xlink:label="lab_aon_FarmingtonAdministrativeServicesLLCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Farmington Administrative Services L L C [Member] </link:label>
<link:label id="lab_aon_FarmingtonAdministrativeServicesLLCMember_documentation_en-US" xlink:label="lab_aon_FarmingtonAdministrativeServicesLLCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Farmington Administrative Services L L C </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FarmingtonAdministrativeServicesLLCMember" xlink:href="aon-20211231.xsd#aon_FarmingtonAdministrativeServicesLLCMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FarmingtonAdministrativeServicesLLCMember" xlink:to="lab_aon_FarmingtonAdministrativeServicesLLCMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther_e3254e43-6f7c-4ed4-858a-33ccbb4040f0_terseLabel_en-US" xlink:label="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency translation and other </link:label>
<link:label id="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther_label_en-US" xlink:label="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance For Credit Loss, Foreign Currency Translation And Other </link:label>
<link:label id="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther_documentation_en-US" xlink:label="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance For Credit Loss, Foreign Currency Translation And Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:href="aon-20211231.xsd#aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:to="lab_aon_AccountsReceivableAllowanceForCreditLossForeignCurrencyTranslationAndOther" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongtermDebtTypeDomain_55fb363d-8de2-4d85-ab9c-148d3527856b_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Type [Domain] </link:label>
<link:label id="lab_us-gaap_LongtermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Type [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeDomain" xlink:to="lab_us-gaap_LongtermDebtTypeDomain" xlink:type="arc" order="1"/>
<link:label id="lab_srt_ScenarioPreviouslyReportedMember_20037091-47ac-4da9-a1cd-935d8b26758b_terseLabel_en-US" xlink:label="lab_srt_ScenarioPreviouslyReportedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> As Reported </link:label>
<link:label id="lab_srt_ScenarioPreviouslyReportedMember_label_en-US" xlink:label="lab_srt_ScenarioPreviouslyReportedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Previously Reported [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioPreviouslyReportedMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScenarioPreviouslyReportedMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScenarioPreviouslyReportedMember" xlink:to="lab_srt_ScenarioPreviouslyReportedMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member_2bb0e1d9-28e2-454f-bd78-573ee2c9a76a_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 4.00% Senior Notes due 2023 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.000 Senior Notes Due 2023 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.000 Senior Notes Due 2023 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:to="lab_aon_GuaranteesOfAonPlcs4000SeniorNotesDue2023Member" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityInformationLineItems_78c828a4-da9b-4c25-ad2b-8699495bc67c_terseLabel_en-US" xlink:label="lab_dei_EntityInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Information [Line Items] </link:label>
<link:label id="lab_dei_EntityInformationLineItems_label_en-US" xlink:label="lab_dei_EntityInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Information [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityInformationLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityInformationLineItems" xlink:to="lab_dei_EntityInformationLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_7df6fe0b-8c68-4faf-b7e5-736dcfd29e3a_terseLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other income </link:label>
<link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_label_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Nonoperating Income (Expense) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:to="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebtFairValue_af1ea5d7-f4fe-484f-a422-d6908a0dc919_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value of long term debt </link:label>
<link:label id="lab_us-gaap_LongTermDebtFairValue_label_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtFairValue" xlink:to="lab_us-gaap_LongTermDebtFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_IncomeTaxAuthorityTable_35b9ddeb-289f-4d42-9b61-d5084d65ecad_terseLabel_en-US" xlink:label="lab_aon_IncomeTaxAuthorityTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Table] </link:label>
<link:label id="lab_aon_IncomeTaxAuthorityTable_label_en-US" xlink:label="lab_aon_IncomeTaxAuthorityTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Table] </link:label>
<link:label id="lab_aon_IncomeTaxAuthorityTable_documentation_en-US" xlink:label="lab_aon_IncomeTaxAuthorityTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> A table or schedule providing information by tax authority. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_IncomeTaxAuthorityTable" xlink:href="aon-20211231.xsd#aon_IncomeTaxAuthorityTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncomeTaxAuthorityTable" xlink:to="lab_aon_IncomeTaxAuthorityTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EquitySecuritiesIndustryMember_32366699-4d86-4129-9567-67e688c64631_terseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesIndustryMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Industry Sector [Domain] </link:label>
<link:label id="lab_us-gaap_EquitySecuritiesIndustryMember_label_en-US" xlink:label="lab_us-gaap_EquitySecuritiesIndustryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Industry Sector [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesIndustryMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesIndustryMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquitySecuritiesIndustryMember" xlink:to="lab_us-gaap_EquitySecuritiesIndustryMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_23e2b211-47be-4821-8392-aa79244fd3a4_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:to="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsDeferredIncome_6db7dc84-a925-442e-8271-0059765ee550_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsDeferredIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred revenue </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsDeferredIncome_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsDeferredIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Deferred Income </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsDeferredIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsDeferredIncome"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsDeferredIncome" xlink:to="lab_us-gaap_DeferredTaxAssetsDeferredIncome" xlink:type="arc" order="1"/>
<link:label id="lab_srt_MaximumMember_f7bb2cd4-a4cf-4207-9ba6-2eedc71820ac_terseLabel_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Maximum </link:label>
<link:label id="lab_srt_MaximumMember_label_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Maximum [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MaximumMember" xlink:to="lab_srt_MaximumMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_2fe196d1-bda7-49d6-b039-423731941d78_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement [Abstract] </link:label>
<link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_650ff720-3995-4f12-9bea-17761e4e6adc_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of the income tax provisions based on the statutory corporate tax rate to the provisions reflected in the Consolidated Financial Statements </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Percent [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract"/>
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<link:label id="lab_us-gaap_GuaranteeObligationsByNatureAxis_c9033ebf-9ee9-4524-8f14-60619723e2bd_terseLabel_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsByNatureAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Nature [Axis] </link:label>
<link:label id="lab_us-gaap_GuaranteeObligationsByNatureAxis_label_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsByNatureAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Nature [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis" xlink:to="lab_us-gaap_GuaranteeObligationsByNatureAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInReceivables_9c2752f8-b075-4fda-a7ee-f04ecf4985fa_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInReceivables" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Receivables, net </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInReceivables_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInReceivables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Receivables </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInReceivables" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInReceivables"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInReceivables" xlink:to="lab_us-gaap_IncreaseDecreaseInReceivables" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AwardTypeAxis_6b5914bc-5050-49d7-b05e-d4e5175513e4_terseLabel_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Award Type [Axis] </link:label>
<link:label id="lab_us-gaap_AwardTypeAxis_label_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Award Type [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AwardTypeAxis" xlink:to="lab_us-gaap_AwardTypeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeTaxesReceivableNoncurrent_91327534-607a-4604-a9b1-f7156bac513e_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesReceivableNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Taxes receivable </link:label>
<link:label id="lab_us-gaap_IncomeTaxesReceivableNoncurrent_label_en-US" xlink:label="lab_us-gaap_IncomeTaxesReceivableNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Taxes Receivable, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesReceivableNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesReceivableNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxesReceivableNoncurrent" xlink:to="lab_us-gaap_IncomeTaxesReceivableNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_e0a93bb3-774a-4f82-8aee-8fd19ab64d2f_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash flows from financing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Financing Activities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_57f3265f-668f-415d-8123-e4ea271badd2_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee Operating Lease Liability Maturity </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, Maturity [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockholdersEquity_ada6980a-4bea-4430-9b2b-5fa11700b1d8_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total Aon shareholders' equity </link:label>
<link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stockholders' Equity Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShorttermDebtFairValue_d7c8df66-4caf-4911-b530-e7d96bd13495_terseLabel_en-US" xlink:label="lab_us-gaap_ShorttermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value current portion of long-term debt </link:label>
<link:label id="lab_us-gaap_ShorttermDebtFairValue_label_en-US" xlink:label="lab_us-gaap_ShorttermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShorttermDebtFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShorttermDebtFairValue" xlink:to="lab_us-gaap_ShorttermDebtFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember_e97c6f10-f5ce-4b90-a601-36ad3b54c31a_terseLabel_en-US" xlink:label="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Money market funds </link:label>
<link:label id="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember_label_en-US" xlink:label="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Money Market Funds and Other Highly Liquid Debt Securities [Member] </link:label>
<link:label id="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember_documentation_en-US" xlink:label="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the money market funds and other highly liquid securities owned by the entity. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:href="aon-20211231.xsd#aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:to="lab_aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_dei_CityAreaCode_241a25bc-260d-4213-9e7a-7ac0b0fa925e_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> City Area Code </link:label>
<link:label id="lab_dei_CityAreaCode_label_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> City Area Code </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CityAreaCode"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CityAreaCode" xlink:to="lab_dei_CityAreaCode" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_1ca8446e-4bda-4a75-a9c5-754c31fa4c25_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts payable and accrued liabilities </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Accounts Payable and Accrued Liabilities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DesignatedAsHedgingInstrumentMember_1989c9c5-774f-4768-95f9-b3d6afc51759_terseLabel_en-US" xlink:label="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounted for as hedges </link:label>
<link:label id="lab_us-gaap_DesignatedAsHedgingInstrumentMember_label_en-US" xlink:label="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Designated as Hedging Instrument [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:to="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_6a358864-a420-46e2-912a-afb25e222e9f_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill and Intangible Assets Disclosure [Abstract] </link:label>
<link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill and Intangible Assets Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_country_IE_45fce20e-cf5c-471a-b0b9-cea668763601_terseLabel_en-US" xlink:label="lab_country_IE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ireland </link:label>
<link:label id="lab_country_IE_label_en-US" xlink:label="lab_country_IE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> IRELAND </link:label>
<link:loc xlink:type="locator" xlink:label="loc_country_IE" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_IE"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_IE" xlink:to="lab_country_IE" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAssetsMiscellaneousNoncurrent_b6ee07a5-c74a-4484-a77b-f6467def4eec_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_OtherAssetsMiscellaneousNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Assets, Miscellaneous, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMiscellaneousNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:to="lab_us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_04718e40-5837-4f28-80b0-df25c90cf28c_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed assets, original life, weighted-average </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Useful Life </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther_8d0802e5-0a05-4184-8fcd-7d469a958c17_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other accrued expenses </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:to="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsOther" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member_2d767782-99ad-4af7-b3e6-b66b849c7ba1_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.05% Senior Notes due 2031 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.05 Senior Notes Due 2031 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.05 Senior Notes Due 2031 </link:label>
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<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member" xlink:to="lab_aon_GuaranteesOfAonPlcs205SeniorNotesDue2031Member" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset_cecc5bf0-841f-4469-9dfd-f4079471027a_totalLabel_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total lease assets </link:label>
<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset_label_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease And Finance Lease, Right-of-Use Asset </link:label>
<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset_documentation_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease And Finance Lease, Right-of-Use Asset </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:href="aon-20211231.xsd#aon_OperatingLeaseAndFinanceLeaseRightofUseAsset"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:to="lab_aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_7692fff4-59c8-4125-8696-982861f7886a_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-current operating lease liabilities </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_bee6cda1-ded2-49f1-b465-b517d8d50ec0_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Liability, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue_c18b37ae-0b53-4274-9e06-9205d353611e_totalLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Imputed interest </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Payment, Due </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefit_233286a7-de42-4fea-860e-4b282a3189d1_terseLabel_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total current tax expense </link:label>
<link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Income Tax Expense (Benefit) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentFaceAmount_d7eb9259-4468-44d7-b112-7f0139776730_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt face value </link:label>
<link:label id="lab_us-gaap_DebtInstrumentFaceAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument, Face Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentFaceAmount" xlink:to="lab_us-gaap_DebtInstrumentFaceAmount" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet_75761e64-28e6-435f-b368-239637f0e000_terseLabel_en-US" xlink:label="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency translation and other </link:label>
<link:label id="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet_label_en-US" xlink:label="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Foreign Currency And Other Adjustments Net </link:label>
<link:label id="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet_documentation_en-US" xlink:label="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Foreign Currency And Other Adjustments Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:href="aon-20211231.xsd#aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:to="lab_aon_CapitalizedContractCostForeignCurrencyAndOtherAdjustmentsNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_cf2df075-0ad5-4602-9f09-4bbfc4746d1e_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total net periodic benefit cost (income) </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_61606e1f-888b-416f-b7b2-6cec4c7782b7_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net periodic benefit cost recognized (millions) </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Net Periodic Benefit Cost (Credit) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_261de30d-42b7-4c6e-8e54-ca5ad7fa56fb_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tax benefit </link:label>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Expense, Tax Benefit </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_6feff891-b66f-437c-9ba2-d3e5b7b9a963_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Defined Benefit Plans Disclosures [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Defined Benefit Plans Disclosures [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingSegmentsMember_d7de2285-96ac-4ac9-81db-93707a56cd64_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Segments </link:label>
<link:label id="lab_us-gaap_OperatingSegmentsMember_label_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Segments [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingSegmentsMember" xlink:to="lab_us-gaap_OperatingSegmentsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_928d0148-bd6e-4f2c-9ceb-00c107beac11_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted share units </link:label>
<link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_8e6bcc3a-37af-445e-8d44-efe088c8e0a2_verboseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted share units (RSUs) </link:label>
<link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_label_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted Stock Units (RSUs) [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:to="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_11832c87-bb15-47af-ac72-11a19b198b66_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consideration Transferred and Preliminary Value of Intangible Assets </link:label>
<link:label id="lab_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock"/>
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<link:label id="lab_srt_RestatementDomain_dd53bea7-d339-45e2-bdc1-c93b2e78b967_terseLabel_en-US" xlink:label="lab_srt_RestatementDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period [Domain] </link:label>
<link:label id="lab_srt_RestatementDomain_label_en-US" xlink:label="lab_srt_RestatementDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RestatementDomain" xlink:to="lab_srt_RestatementDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiability_969f8e25-d04f-4b00-9d41-00749e1a977b_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Present value of lease liabilities </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiability_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiability"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiability" xlink:to="lab_us-gaap_FinanceLeaseLiability" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_68b06dec-2f5b-402d-a6d3-2d3cac3947d1_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plans with ABO in excess of the fair value of plan assets, fair value of plan assets </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets"/>
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<link:label id="lab_us-gaap_BusinessAcquisitionLineItems_a8d4da14-2253-4762-afe1-42569b500b46_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition [Line Items] </link:label>
<link:label id="lab_us-gaap_BusinessAcquisitionLineItems_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems" xlink:to="lab_us-gaap_BusinessAcquisitionLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_8f46e477-c45c-410f-9ee0-832bd18fc33c_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity securities </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Equity Securities [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember" xlink:to="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NoncurrentLeaseLiabilitiesAbstract_28726bf8-a7f6-41ed-ae98-a75ed95fa317_terseLabel_en-US" xlink:label="lab_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-current lease liabilities </link:label>
<link:label id="lab_aon_NoncurrentLeaseLiabilitiesAbstract_label_en-US" xlink:label="lab_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-current Lease Liabilities [Abstract] </link:label>
<link:label id="lab_aon_NoncurrentLeaseLiabilitiesAbstract_documentation_en-US" xlink:label="lab_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-current Lease Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:href="aon-20211231.xsd#aon_NoncurrentLeaseLiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:to="lab_aon_NoncurrentLeaseLiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CapitalizedContractCostImpairmentLoss_1bcb1145-754e-4e68-a6ec-36ca687df89a_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostImpairmentLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Impairment </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostImpairmentLoss_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostImpairmentLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Impairment Loss </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostImpairmentLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalizedContractCostImpairmentLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostImpairmentLoss" xlink:to="lab_us-gaap_CapitalizedContractCostImpairmentLoss" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract_35645a6d-6d42-4d25-8038-b9fb330df5d3_terseLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of cash and cash equivalents and funds held on behalf of clients: </link:label>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeStatementAbstract_6b1df27b-1dbf-4ec0-baa4-e410e42be05d_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Condensed Consolidating Statement of Income </link:label>
<link:label id="lab_us-gaap_IncomeStatementAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Statement [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="lab_us-gaap_IncomeStatementAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member_b9cd7f9e-feac-4c85-b593-0f5c30902e7c_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 4.25% Senior Notes due 2042 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.250 Senior Notes Due 2042 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.250 Senior Notes Due 2042 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:to="lab_aon_GuaranteesOfAonPlcs4250SeniorNotesDue2042Member" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityRegistrantName_86ec6144-0925-478c-b8b8-4f3d021ba989_terseLabel_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Registrant Name </link:label>
<link:label id="lab_dei_EntityRegistrantName_label_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Registrant Name </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityRegistrantName"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityRegistrantName" xlink:to="lab_dei_EntityRegistrantName" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_12810033-09ee-4381-9021-e28a40a1030c_terseLabel_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Aon's deferred tax assets and liabilities </link:label>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_label_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Deferred Tax Assets and Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:to="lab_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne_0c998c35-d57c-4ae6-a090-ec8bd0936c5d_totalLabel_en-US" xlink:label="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
<link:label id="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne_label_en-US" xlink:label="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year One </link:label>
<link:label id="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne_documentation_en-US" xlink:label="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:href="aon-20211231.xsd#aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:to="lab_aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearOne" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_85bb8738-b5dc-4968-b81e-0ce9d35564e4_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, to be Paid, Year Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_383d9a37-d709-4dc1-a442-121146919ad5_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2025 </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, to be Paid, Year Four </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_c7d96e24-21cd-4d16-8589-9d8057791a01_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income tax expense </link:label>
<link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_d3913602-2ac6-467d-9812-0b6e714ac483_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total income tax expense </link:label>
<link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Expense (Benefit) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_59d36e09-ff10-4bea-9982-c79bec830574_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_d849916f-621d-44ef-a327-177f08825bf3_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected future benefit payments 2024 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, Year Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccountsReceivableNetCurrent_9a62b558-6829-4818-9b5f-fef2de39616d_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Receivables, net </link:label>
<link:label id="lab_us-gaap_AccountsReceivableNetCurrent_label_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, after Allowance for Credit Loss, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNetCurrent"/>
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<link:label id="lab_srt_AsiaPacificMember_1309af31-01c2-4909-a189-f346d1856023_terseLabel_en-US" xlink:label="lab_srt_AsiaPacificMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Asia Pacific </link:label>
<link:label id="lab_srt_AsiaPacificMember_label_en-US" xlink:label="lab_srt_AsiaPacificMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Asia Pacific [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AsiaPacificMember"/>
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<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a244ef0a-98c1-4aaf-be76-dbaa6df915a6_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Income (Loss) [Table] </link:label>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Income (Loss) [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
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<link:label id="lab_dei_EntityTaxIdentificationNumber_f89024a2-4125-41ab-8ff9-6915e6964330_terseLabel_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Tax Identification Number </link:label>
<link:label id="lab_dei_EntityTaxIdentificationNumber_label_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Tax Identification Number </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityTaxIdentificationNumber"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityTaxIdentificationNumber" xlink:to="lab_dei_EntityTaxIdentificationNumber" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_0dbaff1a-a547-495a-89b3-3463961e1fd5_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change in fair value of plan assets </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>
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<link:label id="lab_dei_DocumentFiscalPeriodFocus_8a579b14-b9f7-470e-ae86-7bcb553eba92_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Fiscal Period Focus </link:label>
<link:label id="lab_dei_DocumentFiscalPeriodFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Fiscal Period Focus </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalPeriodFocus"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalPeriodFocus" xlink:to="lab_dei_DocumentFiscalPeriodFocus" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AssetsCurrent_bb59a290-3606-48d6-a3d1-4cca4f663426_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total current assets </link:label>
<link:label id="lab_us-gaap_AssetsCurrent_label_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="lab_us-gaap_AssetsCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_4a6e14ae-1a3a-4996-bc7c-8ef13b92479c_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
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<link:label id="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts_17bf341b-7d7e-4312-9b3b-2d3e2b6fe14c_terseLabel_en-US" xlink:label="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additional associated costs </link:label>
<link:label id="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts_label_en-US" xlink:label="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Acquired, Additional Transaction Costs </link:label>
<link:label id="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts_documentation_en-US" xlink:label="lab_aon_TreasuryStockAcquiredAdditionalTransactionCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Acquired, Additional Transaction Costs </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_TreasuryStockAcquiredAdditionalTransactionCosts" xlink:href="aon-20211231.xsd#aon_TreasuryStockAcquiredAdditionalTransactionCosts"/>
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<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_2ec4d7b4-0574-4edc-b64c-f7033f84289f_totalLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total undiscounted future minimum lease payments </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_cf32c78d-a14f-4d77-a5e1-cb0bdeacf198_negatedLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Forfeited (in shares) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
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<link:label id="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization_dadced9c-3e6d-43d3-8a16-53c7ead08ce9_terseLabel_en-US" xlink:label="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-lived assets, including operating lease ROU assets </link:label>
<link:label id="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization_label_en-US" xlink:label="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant And Equipment And Operating Lease Right-Of-Use Asset, After Accumulated Depreciation and Amortization </link:label>
<link:label id="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization_documentation_en-US" xlink:label="lab_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant And Equipment And Operating Lease Right-Of-Use Asset, After Accumulated Depreciation and Amortization </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" xlink:href="aon-20211231.xsd#aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization"/>
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<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_9b2e30f2-c0d5-4bc8-9ba5-f222e17ff913_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (loss) reclassified from accumulated other comprehensive loss, after adoption of ASU 2017-02 </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax"/>
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<link:label id="lab_us-gaap_StockRepurchasedDuringPeriodValue_51c03cfc-f9bc-434f-8281-6f3e772a9ddb_negatedLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodValue" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares purchased </link:label>
<link:label id="lab_us-gaap_StockRepurchasedDuringPeriodValue_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stock Repurchased During Period, Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedDuringPeriodValue" xlink:to="lab_us-gaap_StockRepurchasedDuringPeriodValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_e760e9a0-eec6-4945-8efb-710559540858_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Financial Position [Abstract] </link:label>
<link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Financial Position [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:to="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_f4e3013d-294b-4339-ae68-94c4449d10ce_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Measurements </link:label>
<link:label id="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Measurement, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:to="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_1d9a82d3-edaa-4149-97a3-cd6b4381fc0c_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Type [Domain] </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Lived Tangible Asset [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_e4885f47-797a-4f78-977d-10398ef6834a_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Components of Weighted Average Number of Shares Outstanding </link:label>
<link:label id="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Weighted Average Number of Shares [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FiduciaryReceivables_3348eec9-eb1f-4361-855d-d105964955c8_terseLabel_en-US" xlink:label="lab_aon_FiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary receivables </link:label>
<link:label id="lab_aon_FiduciaryReceivables_label_en-US" xlink:label="lab_aon_FiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Receivables </link:label>
<link:label id="lab_aon_FiduciaryReceivables_documentation_en-US" xlink:label="lab_aon_FiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Receivables </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FiduciaryReceivables" xlink:href="aon-20211231.xsd#aon_FiduciaryReceivables"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FiduciaryReceivables" xlink:to="lab_aon_FiduciaryReceivables" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AuditInformationAbstract_label_en-US" xlink:label="lab_aon_AuditInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Audit Information [Abstract] </link:label>
<link:label id="lab_aon_AuditInformationAbstract_documentation_en-US" xlink:label="lab_aon_AuditInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Audit Information [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AuditInformationAbstract" xlink:href="aon-20211231.xsd#aon_AuditInformationAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AuditInformationAbstract" xlink:to="lab_aon_AuditInformationAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost_8f4a7c13-6b27-4d28-8b5f-6895b60daab2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Excess tax benefits related to shared based compensation </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:type="arc" order="1"/>
<link:label id="lab_aon_HealthSolutionsMember_b342165d-6c38-4b71-8207-d9d312eaedc1_terseLabel_en-US" xlink:label="lab_aon_HealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Health Solutions </link:label>
<link:label id="lab_aon_HealthSolutionsMember_label_en-US" xlink:label="lab_aon_HealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Health Solutions [Member] </link:label>
<link:label id="lab_aon_HealthSolutionsMember_documentation_en-US" xlink:label="lab_aon_HealthSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Health Solutions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_HealthSolutionsMember" xlink:href="aon-20211231.xsd#aon_HealthSolutionsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_HealthSolutionsMember" xlink:to="lab_aon_HealthSolutionsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward_3f1a431c-e7ba-4b8b-941c-22a7d9030d5b_terseLabel_en-US" xlink:label="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward] </link:label>
<link:label id="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward_label_en-US" xlink:label="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward] </link:label>
<link:label id="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward_documentation_en-US" xlink:label="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Accumulated Other Comprehensive Income (Loss) [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:href="aon-20211231.xsd#aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:to="lab_aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EquityComponentDomain_41098775-680b-40f3-bce8-ea60095f584b_terseLabel_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Component [Domain] </link:label>
<link:label id="lab_us-gaap_EquityComponentDomain_label_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Component [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxAssetsLeaseGuarantees_58a80cbe-731e-45e3-9886-8821a1d7c291_terseLabel_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseGuarantees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease and service guarantees </link:label>
<link:label id="lab_aon_DeferredTaxAssetsLeaseGuarantees_label_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseGuarantees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Lease Guarantees </link:label>
<link:label id="lab_aon_DeferredTaxAssetsLeaseGuarantees_documentation_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseGuarantees" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Lease Guarantees </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxAssetsLeaseGuarantees" xlink:href="aon-20211231.xsd#aon_DeferredTaxAssetsLeaseGuarantees"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxAssetsLeaseGuarantees" xlink:to="lab_aon_DeferredTaxAssetsLeaseGuarantees" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_ff124f28-8a1b-410c-9f90-dc849cf89b89_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, Year One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_86559eb8-b751-4caa-81e5-9fc357efd096_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Name [Domain] </link:label>
<link:label id="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_label_en-US" xlink:label="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Name [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_8932f574-bc08-4340-b20d-6d633a424c70_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Category [Axis] </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Category [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:to="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_11a4a8cd-e784-49fd-a7a5-d3ddc05261e0_terseLabel_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax assets: </link:label>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Deferred Tax Assets [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:to="lab_us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FatalPlainCrashInNovember2016Member_279e0261-9b55-43a8-8feb-b0e7bbb98f95_terseLabel_en-US" xlink:label="lab_aon_FatalPlainCrashInNovember2016Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fatal Plain Crash In November2016 </link:label>
<link:label id="lab_aon_FatalPlainCrashInNovember2016Member_label_en-US" xlink:label="lab_aon_FatalPlainCrashInNovember2016Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fatal Plain Crash In November2016 [Member] </link:label>
<link:label id="lab_aon_FatalPlainCrashInNovember2016Member_documentation_en-US" xlink:label="lab_aon_FatalPlainCrashInNovember2016Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fatal Plain Crash In November2016 </link:label>
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<link:label id="lab_srt_LitigationCaseAxis_f136eb5c-3657-46c4-a66b-b573a2308ebd_terseLabel_en-US" xlink:label="lab_srt_LitigationCaseAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Case [Axis] </link:label>
<link:label id="lab_srt_LitigationCaseAxis_label_en-US" xlink:label="lab_srt_LitigationCaseAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Case [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_LitigationCaseAxis" xlink:to="lab_srt_LitigationCaseAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DomesticPlanMember_d4cb4d60-92b4-48e0-a9cd-35005a86b313_terseLabel_en-US" xlink:label="lab_us-gaap_DomesticPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Domestic Plan </link:label>
<link:label id="lab_us-gaap_DomesticPlanMember_label_en-US" xlink:label="lab_us-gaap_DomesticPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Domestic Plan [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticPlanMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DomesticPlanMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DomesticPlanMember" xlink:to="lab_us-gaap_DomesticPlanMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_c4417480-e515-4b34-bf62-bfb796338565_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Impairment of intangible assets </link:label>
<link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Impairment of Intangible Assets, Finite-lived </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:to="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShortTermDebtTypeAxis_3a30b690-99cd-42af-a918-cdbe2d2c7c45_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Type [Axis] </link:label>
<link:label id="lab_us-gaap_ShortTermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Type [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis" xlink:to="lab_us-gaap_ShortTermDebtTypeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LiabilitiesAbstract_11cce25b-0ab7-4ff9-9c6e-f10cd1699554_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities </link:label>
<link:label id="lab_us-gaap_LiabilitiesAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="lab_us-gaap_LiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_005f703c-6ba7-4b88-bcf2-48bf1908ed15_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Expense Recognized in Continuing Operations </link:label>
<link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Cost by Plan [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_cbc8723c-cb4e-4d8b-b98d-d7ac860bda7a_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Adjustments to valuation allowances </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NumberOfPerformanceMetricsMeasured_6498b5f4-5a57-471c-953d-085e83fd12c4_terseLabel_en-US" xlink:label="lab_aon_NumberOfPerformanceMetricsMeasured" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of performance metrics measured </link:label>
<link:label id="lab_aon_NumberOfPerformanceMetricsMeasured_label_en-US" xlink:label="lab_aon_NumberOfPerformanceMetricsMeasured" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number Of Performance Metrics Measured </link:label>
<link:label id="lab_aon_NumberOfPerformanceMetricsMeasured_documentation_en-US" xlink:label="lab_aon_NumberOfPerformanceMetricsMeasured" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number Of Performance Metrics Measured </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NumberOfPerformanceMetricsMeasured" xlink:href="aon-20211231.xsd#aon_NumberOfPerformanceMetricsMeasured"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NumberOfPerformanceMetricsMeasured" xlink:to="lab_aon_NumberOfPerformanceMetricsMeasured" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_1d82847b-a1a4-4623-a817-50dd05ba8fe8_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2025 </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, Year Four </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityCurrent_a6087c86-324a-42c1-9aaa-7298fbd828e1_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityCurrent" xlink:to="lab_us-gaap_FinanceLeaseLiabilityCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInRestructuringReserve_6645a0ff-631c-44c7-aa09-0dfa0a8af1be_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restructuring reserves </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInRestructuringReserve_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Restructuring Reserve </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInRestructuringReserve"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:to="lab_us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_e9af9356-75d7-42c7-92c8-3ed4a119bb51_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income before income taxes </link:label>
<link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueInputsLevel2Member_ced57621-b442-4025-a851-f9433b1c3f51_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Significant Other Observable Inputs (Level 2) </link:label>
<link:label id="lab_us-gaap_FairValueInputsLevel2Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Inputs, Level 2 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel2Member" xlink:to="lab_us-gaap_FairValueInputsLevel2Member" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset_d6d1425d-c92c-4100-9693-1d4f037f3953_negatedTerseLabel_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease right-of-use asset </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset_label_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Lease Right-of-Use Asset </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset_documentation_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Lease Right-of-Use Asset </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:href="aon-20211231.xsd#aon_DeferredTaxLiabilitiesLeaseRightofUseAsset"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:to="lab_aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock_f6d6d9f6-095c-45c2-8244-063990c37853_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Error Corrections and Prior Period Adjustments </link:label>
<link:label id="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock" xlink:to="lab_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentsTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ContractWithCustomerLiabilityNoncurrent_92c77c30-9f21-4049-993e-ebc596cad942_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred revenue </link:label>
<link:label id="lab_us-gaap_ContractWithCustomerLiabilityNoncurrent_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract with Customer, Liability, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:to="lab_us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_dei_AuditorLocation_80d62ecc-e5da-449a-82da-16837f7d3262_terseLabel_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Location </link:label>
<link:label id="lab_dei_AuditorLocation_label_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Location </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_AuditorLocation" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorLocation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorLocation" xlink:to="lab_dei_AuditorLocation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeGainLossOnDerivativeNet_15c8f541-13ad-4516-860e-ba48d7354c5a_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial instruments </link:label>
<link:label id="lab_us-gaap_DerivativeGainLossOnDerivativeNet_2f3a7d4f-95d4-4353-9932-7f3af01df0ea_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (loss) on derivative </link:label>
<link:label id="lab_us-gaap_DerivativeGainLossOnDerivativeNet_label_en-US" xlink:label="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative, Gain (Loss) on Derivative, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:to="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SegmentReportingAbstract_917df539-9cbc-4517-90be-0230c53a363d_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Segment Reporting [Abstract] </link:label>
<link:label id="lab_us-gaap_SegmentReportingAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Segment Reporting [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract" xlink:to="lab_us-gaap_SegmentReportingAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife_50f2eda0-bc38-4c65-b77f-e08a05f5e5b2_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Useful life of finite-lived intangible assets </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Useful Life </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseInterestExpense_96835a93-6494-454e-bce1-59872a41ce86_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest on lease liabilities </link:label>
<link:label id="lab_us-gaap_FinanceLeaseInterestExpense_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Interest Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseInterestExpense"/>
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<link:label id="lab_us-gaap_UseOfEstimates_e190c481-f4b9-42cc-a3f1-04579607a5fb_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Use of Estimates </link:label>
<link:label id="lab_us-gaap_UseOfEstimates_label_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Use of Estimates, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UseOfEstimates"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UseOfEstimates" xlink:to="lab_us-gaap_UseOfEstimates" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_b19627b0-d6a4-4929-9fa5-dff2287d9bc4_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total other comprehensive income (loss) attributable to Aon shareholders </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
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<link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_99724912-6fae-4a8b-9e51-55d6c2ab3a6c_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Leases </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Payment, Due [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:to="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_dei_Security12bTitle_6a34e3a7-c8b1-4856-9726-7d03a6b644d7_terseLabel_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Title of 12(b) Security </link:label>
<link:label id="lab_dei_Security12bTitle_label_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Title of 12(b) Security </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_Security12bTitle"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_Security12bTitle" xlink:to="lab_dei_Security12bTitle" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock_8d89abad-0e09-4beb-a354-dbfaa2f4be55_terseLabel_en-US" xlink:label="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and Cash Equivalents and Short-term Investments </link:label>
<link:label id="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock_label_en-US" xlink:label="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Cash Equivalents and Short Term Investments [Policy Text Block] </link:label>
<link:label id="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock_documentation_en-US" xlink:label="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disclosure of accounting policy for cash and cash equivalents and short-term investments. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:href="aon-20211231.xsd#aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:to="lab_aon_CashCashEquivalentsAndShortTermInvestmentsPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_srt_RestatementAdjustmentMember_04b7b9bc-1684-452f-ae80-bd8b8399a655_terseLabel_en-US" xlink:label="lab_srt_RestatementAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effect of Change </link:label>
<link:label id="lab_srt_RestatementAdjustmentMember_label_en-US" xlink:label="lab_srt_RestatementAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period, Adjustment [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAdjustmentMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementAdjustmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RestatementAdjustmentMember" xlink:to="lab_srt_RestatementAdjustmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredIncomeTaxesAndTaxCredits_7e156b7c-9904-4d6a-bf12-034b20421b7c_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred income taxes </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxesAndTaxCredits_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Taxes and Tax Credits </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:to="lab_us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsToMinorityShareholders_683612cd-3246-4d04-882c-eed48547a946_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToMinorityShareholders" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Noncontrolling interests and other financing activities </link:label>
<link:label id="lab_us-gaap_PaymentsToMinorityShareholders_label_en-US" xlink:label="lab_us-gaap_PaymentsToMinorityShareholders" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to Noncontrolling Interests </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToMinorityShareholders"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToMinorityShareholders" xlink:to="lab_us-gaap_PaymentsToMinorityShareholders" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockSharesAuthorized_ed5eba61-56a7-4d7c-90d0-b85caef8484d_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ordinary shares, authorized shares (in Shares) </link:label>
<link:label id="lab_us-gaap_CommonStockSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock, Shares Authorized </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesAuthorized" xlink:to="lab_us-gaap_CommonStockSharesAuthorized" xlink:type="arc" order="1"/>
<link:label id="lab_dei_DocumentType_e3bcca15-f910-41ce-ac19-ec774137a528_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Type </link:label>
<link:label id="lab_dei_DocumentType_label_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Type </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentType"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentType" xlink:to="lab_dei_DocumentType" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferredAbstract_94e6bae2-c30a-417d-847a-28a64c8deab0_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consideration transferred </link:label>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferredAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Consideration Transferred [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:to="lab_us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_srt_ProductsAndServicesDomain_eaaee0e2-5e2d-4da8-8440-541fc98407e1_terseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Product and Service [Domain] </link:label>
<link:label id="lab_srt_ProductsAndServicesDomain_label_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Product and Service [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards_4ddc8490-564f-4f75-93d5-efc641888876_terseLabel_en-US" xlink:label="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net operating loss, capital loss, interest, and tax credit carryforwards </link:label>
<link:label id="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards_label_en-US" xlink:label="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets Net Operating and Capital Loss Carryforwards and Tax Credit Carryforwards </link:label>
<link:label id="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards_documentation_en-US" xlink:label="lab_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The sum of the tax effects as of the balance sheet date of the amount of (1) excess of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset, and capital losses that cannot be utilized on the tax return during a period that have been carried forward to reduce taxable income or taxes payable in a future year and (2) future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" xlink:href="aon-20211231.xsd#aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards"/>
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<link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_bb3fc28e-02d4-44c7-b48f-7f51b89f4d00_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest rate on debt </link:label>
<link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_f8b8744b-c3f3-4a66-8180-2a85f4ba56d4_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt interest rate percentage (as a percent) </link:label>
<link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument, Interest Rate, Stated Percentage </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
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<link:label id="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_e9521ab9-75b9-4d8f-ae82-b50a9881c740_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Net income attributable to noncontrolling interests </link:label>
<link:label id="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Income (Loss) Attributable to Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
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<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f7ce0d70-6808-42ca-94af-4f09384aed16_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award [Line Items] </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
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<link:label id="lab_aon_FinanceLeaseCost1Abstract_a9b592a1-3d63-4f42-8f9c-e701e362ce5a_terseLabel_en-US" xlink:label="lab_aon_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance lease costs </link:label>
<link:label id="lab_aon_FinanceLeaseCost1Abstract_label_en-US" xlink:label="lab_aon_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Cost1 [Abstract] </link:label>
<link:label id="lab_aon_FinanceLeaseCost1Abstract_documentation_en-US" xlink:label="lab_aon_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Cost1 [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinanceLeaseCost1Abstract" xlink:href="aon-20211231.xsd#aon_FinanceLeaseCost1Abstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinanceLeaseCost1Abstract" xlink:to="lab_aon_FinanceLeaseCost1Abstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation_d4b32af9-4724-47bf-a0ca-36a7ae2fb3b8_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency translation </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromForeignCurrencyTranslation"/>
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<link:label id="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings_c3b5eae7-8194-48de-9bfa-14e3388d1570_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unremitted earnings </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings_3a37506d-7988-4770-905a-cd21695d6958_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unremitted earnings </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Undistributed Foreign Earnings </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets_7a01a3ca-0ee7-47ac-805c-598b3c2d52c3_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plans with PBO in excess of plan assets, plan assets </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets"/>
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<link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_dd1522a0-d5c8-4075-ae43-b97f9a04b5ac_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Measurement Frequency [Axis] </link:label>
<link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Measurement Frequency [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LeaseCostTableTextBlock_fc00e2a1-6b60-43af-9d75-ed45f3e19b94_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease, Cost </link:label>
<link:label id="lab_us-gaap_LeaseCostTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease, Cost [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCostTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCostTableTextBlock" xlink:to="lab_us-gaap_LeaseCostTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CorporateBondSecuritiesMember_a746d26b-a0cb-424b-9be1-c9725c753c87_terseLabel_en-US" xlink:label="lab_us-gaap_CorporateBondSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Corporate bonds </link:label>
<link:label id="lab_us-gaap_CorporateBondSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_CorporateBondSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Corporate Bond Securities [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateBondSecuritiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CorporateBondSecuritiesMember" xlink:to="lab_us-gaap_CorporateBondSecuritiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations_ff1a5169-4ba9-4571-bca0-f25e8c7a6948_terseLabel_en-US" xlink:label="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Percentage of the Company's projected benefit obligation </link:label>
<link:label id="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations_label_en-US" xlink:label="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Percentage of the Total Pension Obligations </link:label>
<link:label id="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations_documentation_en-US" xlink:label="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the percentage of the company's total pension obligations represented within the tables provided. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:href="aon-20211231.xsd#aon_DefinedBenefitPlanPercentageOfTotalPensionObligations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:to="lab_aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" xlink:type="arc" order="1"/>
<link:label id="lab_srt_StatementGeographicalAxis_688ddecc-1fd3-482e-a0ea-c2a1944a4a1d_terseLabel_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Geographical [Axis] </link:label>
<link:label id="lab_srt_StatementGeographicalAxis_label_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Geographical [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_StatementGeographicalAxis" xlink:to="lab_srt_StatementGeographicalAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_301f9266-1e3d-4dc7-a016-87e6ce34b516_verboseLabel_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. state and local </link:label>
<link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_3fc39860-63ac-49f4-938d-ea626269d82f_terseLabel_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. State </link:label>
<link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_label_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> State and Local Jurisdiction [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StateAndLocalJurisdictionMember" xlink:to="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetInvestmentHedgingMember_e9a53014-63e9-43a2-a3c1-5df40daafbfc_terseLabel_en-US" xlink:label="lab_us-gaap_NetInvestmentHedgingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Investment Hedging </link:label>
<link:label id="lab_us-gaap_NetInvestmentHedgingMember_label_en-US" xlink:label="lab_us-gaap_NetInvestmentHedgingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Investment Hedging [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetInvestmentHedgingMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetInvestmentHedgingMember" xlink:to="lab_us-gaap_NetInvestmentHedgingMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_1bc3a3e3-970c-48d2-a643-2fc771481cb2_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Relationship [Axis] </link:label>
<link:label id="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Relationship [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
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<link:label id="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock_fdced024-9504-4868-8a5a-3cd81c923dfb_terseLabel_en-US" xlink:label="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Acquisitions and Dispositions of Businesses </link:label>
<link:label id="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Mergers, Acquisitions and Dispositions Disclosures [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:to="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_InterestExpenseMember_6f2ecbea-b6af-419b-ae14-76c06f5796ec_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest expense </link:label>
<link:label id="lab_us-gaap_InterestExpenseMember_label_en-US" xlink:label="lab_us-gaap_InterestExpenseMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest Expense [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpenseMember" xlink:to="lab_us-gaap_InterestExpenseMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A2021And2020AcquisitionsMember_a756679c-b0cc-49d5-9a82-afc7e3aa0e51_terseLabel_en-US" xlink:label="lab_aon_A2021And2020AcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2021 And 2020 Acquisitions </link:label>
<link:label id="lab_aon_A2021And2020AcquisitionsMember_label_en-US" xlink:label="lab_aon_A2021And2020AcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2021 And 2020 Acquisitions [Member] </link:label>
<link:label id="lab_aon_A2021And2020AcquisitionsMember_documentation_en-US" xlink:label="lab_aon_A2021And2020AcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2021 And 2020 Acquisitions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A2021And2020AcquisitionsMember" xlink:href="aon-20211231.xsd#aon_A2021And2020AcquisitionsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A2021And2020AcquisitionsMember" xlink:to="lab_aon_A2021And2020AcquisitionsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent_072b8676-f2e8-4d04-97d3-2891d44d499c_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. Tax Reform impact </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent"/>
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<link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_f8c805ae-8bcb-4f44-b18e-4e4e1f57d235_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash used for financing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_a46fafc7-eb0b-47d7-822e-65de4cac995e_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash used for financing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Financing Activities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="arc" order="1"/>
<link:label id="lab_aon_TheNetherlandsAndCanadaMember_c59528b0-14d0-4adc-91d6-cdab483cb3fb_verboseLabel_en-US" xlink:label="lab_aon_TheNetherlandsAndCanadaMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Netherlands and Canada </link:label>
<link:label id="lab_aon_TheNetherlandsAndCanadaMember_5d478da8-f168-4535-aa80-179741a1732f_terseLabel_en-US" xlink:label="lab_aon_TheNetherlandsAndCanadaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_aon_TheNetherlandsAndCanadaMember_label_en-US" xlink:label="lab_aon_TheNetherlandsAndCanadaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The Netherlands And Canada [Member] </link:label>
<link:label id="lab_aon_TheNetherlandsAndCanadaMember_documentation_en-US" xlink:label="lab_aon_TheNetherlandsAndCanadaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The Netherlands And Canada [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_TheNetherlandsAndCanadaMember" xlink:href="aon-20211231.xsd#aon_TheNetherlandsAndCanadaMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_TheNetherlandsAndCanadaMember" xlink:to="lab_aon_TheNetherlandsAndCanadaMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_fb2666e3-ef3a-4979-b2b8-979be9d260a7_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Vesting period </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_5a2dc6f4-744f-4cbc-b4eb-826e074f4436_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accrued potential interest and penalties </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:to="lab_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_7811528b-1e69-4006-ac03-6c8821317ea5_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity earnings </link:label>
<link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (Loss) from Equity Method Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:to="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue_512aa66d-dbee-4792-ac23-0961a25e6f03_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total undiscounted future minimum lease payments </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OtherCarryforwards_fcdcaaec-df01-4022-b31b-39206a450033_terseLabel_en-US" xlink:label="lab_aon_OtherCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other carryforwards </link:label>
<link:label id="lab_aon_OtherCarryforwards_label_en-US" xlink:label="lab_aon_OtherCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Carryforwards </link:label>
<link:label id="lab_aon_OtherCarryforwards_documentation_en-US" xlink:label="lab_aon_OtherCarryforwards" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Carryforwards </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OtherCarryforwards" xlink:href="aon-20211231.xsd#aon_OtherCarryforwards"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OtherCarryforwards" xlink:to="lab_aon_OtherCarryforwards" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A445SeniorNotesDueMay2043Member_a405d7fa-290e-4eef-baaf-46b2d8e0800e_terseLabel_en-US" xlink:label="lab_aon_A445SeniorNotesDueMay2043Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.45% Senior Notes due May 2043 </link:label>
<link:label id="lab_aon_A445SeniorNotesDueMay2043Member_label_en-US" xlink:label="lab_aon_A445SeniorNotesDueMay2043Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.45% Senior Notes Due May 2043 [Member] </link:label>
<link:label id="lab_aon_A445SeniorNotesDueMay2043Member_documentation_en-US" xlink:label="lab_aon_A445SeniorNotesDueMay2043Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.45% Senior Notes Due May 2043 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A445SeniorNotesDueMay2043Member" xlink:href="aon-20211231.xsd#aon_A445SeniorNotesDueMay2043Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A445SeniorNotesDueMay2043Member" xlink:to="lab_aon_A445SeniorNotesDueMay2043Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_c0c26bf8-2ac3-45ad-9a8f-69a7974a3148_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Measurements and Financial Instruments </link:label>
<link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Disclosures [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:to="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_9fa7ddcf-676a-4b3b-8c1c-745181ddf7f7_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Maturity </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Fiscal Year Maturity [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:to="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_e54b14dc-c983-4d48-a6d8-011d190966e7_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Expected Amortization, Year Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ForeignCountryMember_252e2d20-c9b1-465b-91f2-f02cbb1735ab_verboseLabel_en-US" xlink:label="lab_us-gaap_ForeignCountryMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. federal </link:label>
<link:label id="lab_us-gaap_ForeignCountryMember_label_en-US" xlink:label="lab_us-gaap_ForeignCountryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Tax Authority [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCountryMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCountryMember" xlink:to="lab_us-gaap_ForeignCountryMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_PilkingtonNorthAmericaInc.Member_fcfd3f6d-b14d-45bd-b61f-c574f377cd84_terseLabel_en-US" xlink:label="lab_aon_PilkingtonNorthAmericaInc.Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pilkington North America, Inc. </link:label>
<link:label id="lab_aon_PilkingtonNorthAmericaInc.Member_label_en-US" xlink:label="lab_aon_PilkingtonNorthAmericaInc.Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pilkington North America, Inc. [Member] </link:label>
<link:label id="lab_aon_PilkingtonNorthAmericaInc.Member_documentation_en-US" xlink:label="lab_aon_PilkingtonNorthAmericaInc.Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pilkington North America, Inc. [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_PilkingtonNorthAmericaInc.Member" xlink:href="aon-20211231.xsd#aon_PilkingtonNorthAmericaInc.Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_PilkingtonNorthAmericaInc.Member" xlink:to="lab_aon_PilkingtonNorthAmericaInc.Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeTable_844da9a2-b068-4f1c-8144-e8d4cef568df_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative [Table] </link:label>
<link:label id="lab_us-gaap_DerivativeTable_label_en-US" xlink:label="lab_us-gaap_DerivativeTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeTable" xlink:to="lab_us-gaap_DerivativeTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenuesAbstract_cec3d0e5-7266-47e3-ab3b-5d9432c7d0d2_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue </link:label>
<link:label id="lab_us-gaap_RevenuesAbstract_label_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenues [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesAbstract" xlink:to="lab_us-gaap_RevenuesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FixedIncomeInvestmentsPooledFundsMember_f9066c15-95fb-4da4-a72d-45d6411f7d5d_terseLabel_en-US" xlink:label="lab_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed Income Investments, Pooled Funds </link:label>
<link:label id="lab_aon_FixedIncomeInvestmentsPooledFundsMember_label_en-US" xlink:label="lab_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed Income Investments, Pooled Funds [Member] </link:label>
<link:label id="lab_aon_FixedIncomeInvestmentsPooledFundsMember_documentation_en-US" xlink:label="lab_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed Income Investments, Pooled Funds [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:href="aon-20211231.xsd#aon_FixedIncomeInvestmentsPooledFundsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:to="lab_aon_FixedIncomeInvestmentsPooledFundsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComputerSoftwareIntangibleAssetMember_07a44d9f-7668-43fa-9354-4a5190c814a2_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Software </link:label>
<link:label id="lab_us-gaap_ComputerSoftwareIntangibleAssetMember_label_en-US" xlink:label="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Computer Software, Intangible Asset [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:to="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:type="arc" order="1"/>
<link:label id="lab_dei_DocumentPeriodEndDate_207697ef-55fa-45f8-abb6-4a5016f08794_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Period End Date </link:label>
<link:label id="lab_dei_DocumentPeriodEndDate_label_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Period End Date </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentPeriodEndDate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_3515e9c6-263a-4f07-b09f-94684befefb0_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. state income taxes, net of U.S. federal benefit </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_eb582726-bf38-43c0-9bf8-622eb68f4eb6_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Estimated Useful Lives of Assets </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeStatementLocationDomain_049a7cf6-52cb-40fd-8d57-85125913b87a_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Statement Location [Domain] </link:label>
<link:label id="lab_us-gaap_IncomeStatementLocationDomain_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Statement Location [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationDomain" xlink:to="lab_us-gaap_IncomeStatementLocationDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_f7278d83-9510-4457-aa69-6422385a2bda_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed assets, net </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_8367099e-250f-4a02-8af9-0edd62570bed_totalLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed assets, net </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock_caf938ec-7567-46e5-bc3d-2d91a15c6e03_terseLabel_en-US" xlink:label="lab_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shareholders' Equity </link:label>
<link:label id="lab_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shareholders' Equity and Share-based Payments [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:to="lab_us-gaap_ShareholdersEquityAndShareBasedPaymentsTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_1a442ad5-e96a-4556-8a45-12fb1e0a7046_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Estimated Future Amortization Expense on Intangible Assets </link:label>
<link:label id="lab_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:to="lab_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CashandCashEquivalentsandShortTermInvestments_621e6a7d-f953-453d-a449-828ab3c23d26_terseLabel_en-US" xlink:label="lab_aon_CashandCashEquivalentsandShortTermInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents and short-term investments </link:label>
<link:label id="lab_aon_CashandCashEquivalentsandShortTermInvestments_label_en-US" xlink:label="lab_aon_CashandCashEquivalentsandShortTermInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and Cash Equivalents and Short-Term Investments </link:label>
<link:label id="lab_aon_CashandCashEquivalentsandShortTermInvestments_documentation_en-US" xlink:label="lab_aon_CashandCashEquivalentsandShortTermInvestments" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and Cash Equivalents and Short-Term Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CashandCashEquivalentsandShortTermInvestments" xlink:href="aon-20211231.xsd#aon_CashandCashEquivalentsandShortTermInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CashandCashEquivalentsandShortTermInvestments" xlink:to="lab_aon_CashandCashEquivalentsandShortTermInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RepaymentsOfLongTermDebt_7681976d-db1d-4be0-98ef-cd4d508a1fdc_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermDebt" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Repayment of debt </link:label>
<link:label id="lab_us-gaap_RepaymentsOfLongTermDebt_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Repayments of Long-term Debt </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfLongTermDebt" xlink:to="lab_us-gaap_RepaymentsOfLongTermDebt" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AmericasOtherthanUnitedStatesMember_a412e0f6-f918-4767-aa32-b260d1edf155_terseLabel_en-US" xlink:label="lab_aon_AmericasOtherthanUnitedStatesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Americas other than U.S. </link:label>
<link:label id="lab_aon_AmericasOtherthanUnitedStatesMember_label_en-US" xlink:label="lab_aon_AmericasOtherthanUnitedStatesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Americas, Other than United States [Member] </link:label>
<link:label id="lab_aon_AmericasOtherthanUnitedStatesMember_documentation_en-US" xlink:label="lab_aon_AmericasOtherthanUnitedStatesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Americas, Other than United States [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AmericasOtherthanUnitedStatesMember" xlink:href="aon-20211231.xsd#aon_AmericasOtherthanUnitedStatesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AmericasOtherthanUnitedStatesMember" xlink:to="lab_aon_AmericasOtherthanUnitedStatesMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A4.60SeniorNotesDueJune2044Member_e7ad30a0-3def-488c-85f4-9f856dbadd3f_terseLabel_en-US" xlink:label="lab_aon_A4.60SeniorNotesDueJune2044Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.60% Senior Notes due June 2044 </link:label>
<link:label id="lab_aon_A4.60SeniorNotesDueJune2044Member_label_en-US" xlink:label="lab_aon_A4.60SeniorNotesDueJune2044Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.60% Senior Notes Due June 2044 [Member] </link:label>
<link:label id="lab_aon_A4.60SeniorNotesDueJune2044Member_documentation_en-US" xlink:label="lab_aon_A4.60SeniorNotesDueJune2044Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.60% Senior Notes Due June 2044 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A4.60SeniorNotesDueJune2044Member" xlink:href="aon-20211231.xsd#aon_A4.60SeniorNotesDueJune2044Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A4.60SeniorNotesDueJune2044Member" xlink:to="lab_aon_A4.60SeniorNotesDueJune2044Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_85b55d0d-f11a-4d57-84c5-f7cafd5c0caa_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fixed assets, gross </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Gross </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentGross" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OtherTaxAssetsCurrent_7913a9a1-176b-4409-8d3c-2dac0a78006f_terseLabel_en-US" xlink:label="lab_aon_OtherTaxAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Taxes receivable </link:label>
<link:label id="lab_aon_OtherTaxAssetsCurrent_label_en-US" xlink:label="lab_aon_OtherTaxAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Tax Assets, Current </link:label>
<link:label id="lab_aon_OtherTaxAssetsCurrent_documentation_en-US" xlink:label="lab_aon_OtherTaxAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Tax Assets, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OtherTaxAssetsCurrent" xlink:href="aon-20211231.xsd#aon_OtherTaxAssetsCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OtherTaxAssetsCurrent" xlink:to="lab_aon_OtherTaxAssetsCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A4.50SeniorNotesDueDecember2028Member_72cdddab-1602-4057-bed1-e2073018ae6e_terseLabel_en-US" xlink:label="lab_aon_A4.50SeniorNotesDueDecember2028Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.50% Senior Notes due December 2028 </link:label>
<link:label id="lab_aon_A4.50SeniorNotesDueDecember2028Member_label_en-US" xlink:label="lab_aon_A4.50SeniorNotesDueDecember2028Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.50% Senior Notes Due December 2028 [Member] </link:label>
<link:label id="lab_aon_A4.50SeniorNotesDueDecember2028Member_documentation_en-US" xlink:label="lab_aon_A4.50SeniorNotesDueDecember2028Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.50% Senior Notes Due December 2028 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A4.50SeniorNotesDueDecember2028Member" xlink:href="aon-20211231.xsd#aon_A4.50SeniorNotesDueDecember2028Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A4.50SeniorNotesDueDecember2028Member" xlink:to="lab_aon_A4.50SeniorNotesDueDecember2028Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_Revenues_1f18de79-161b-4107-8bd2-ee9dcfb32f0a_terseLabel_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total revenue </link:label>
<link:label id="lab_us-gaap_Revenues_label_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenues </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Revenues" xlink:to="lab_us-gaap_Revenues" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DistributableProfitsApprovedAmount_60a4e2cd-097d-495d-affe-4a785a184739_terseLabel_en-US" xlink:label="lab_aon_DistributableProfitsApprovedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Distributable profits approved amount </link:label>
<link:label id="lab_aon_DistributableProfitsApprovedAmount_label_en-US" xlink:label="lab_aon_DistributableProfitsApprovedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Distributable Profits Approved Amount </link:label>
<link:label id="lab_aon_DistributableProfitsApprovedAmount_documentation_en-US" xlink:label="lab_aon_DistributableProfitsApprovedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Distributable Profits Approved Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DistributableProfitsApprovedAmount" xlink:href="aon-20211231.xsd#aon_DistributableProfitsApprovedAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DistributableProfitsApprovedAmount" xlink:to="lab_aon_DistributableProfitsApprovedAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ForeignExchangeContractMember_cb7459a9-f3e4-4e4b-8a65-f574845478a3_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignExchangeContractMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gross foreign exchange contracts </link:label>
<link:label id="lab_us-gaap_ForeignExchangeContractMember_label_en-US" xlink:label="lab_us-gaap_ForeignExchangeContractMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Exchange Contract [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignExchangeContractMember" xlink:to="lab_us-gaap_ForeignExchangeContractMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AonHewittInvestmentConsultingIncMember_8c9dc635-0a74-49ad-af15-186b721b8760_terseLabel_en-US" xlink:label="lab_aon_AonHewittInvestmentConsultingIncMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon Hewitt Investment Consulting, Inc. </link:label>
<link:label id="lab_aon_AonHewittInvestmentConsultingIncMember_label_en-US" xlink:label="lab_aon_AonHewittInvestmentConsultingIncMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon Hewitt Investment Consulting, Inc. [Member] </link:label>
<link:label id="lab_aon_AonHewittInvestmentConsultingIncMember_documentation_en-US" xlink:label="lab_aon_AonHewittInvestmentConsultingIncMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon Hewitt Investment Consulting, Inc. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AonHewittInvestmentConsultingIncMember" xlink:href="aon-20211231.xsd#aon_AonHewittInvestmentConsultingIncMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AonHewittInvestmentConsultingIncMember" xlink:to="lab_aon_AonHewittInvestmentConsultingIncMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CostsAndExpensesAbstract_358b472b-45da-44fa-bb43-7decceb84045_terseLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expenses </link:label>
<link:label id="lab_us-gaap_CostsAndExpensesAbstract_label_en-US" xlink:label="lab_us-gaap_CostsAndExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Costs and Expenses [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostsAndExpensesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostsAndExpensesAbstract" xlink:to="lab_us-gaap_CostsAndExpensesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NumberofRevenueLines_016e2c6a-23d7-4a3f-9ac4-99c3d39d9a91_terseLabel_en-US" xlink:label="lab_aon_NumberofRevenueLines" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of revenue lines </link:label>
<link:label id="lab_aon_NumberofRevenueLines_label_en-US" xlink:label="lab_aon_NumberofRevenueLines" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Revenue Lines </link:label>
<link:label id="lab_aon_NumberofRevenueLines_documentation_en-US" xlink:label="lab_aon_NumberofRevenueLines" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Revenue Lines </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NumberofRevenueLines" xlink:href="aon-20211231.xsd#aon_NumberofRevenueLines"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NumberofRevenueLines" xlink:to="lab_aon_NumberofRevenueLines" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityCurrentReportingStatus_2df3285b-d54a-4bdc-a384-ca3d52375e8d_terseLabel_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Current Reporting Status </link:label>
<link:label id="lab_dei_EntityCurrentReportingStatus_label_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Current Reporting Status </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCurrentReportingStatus"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCurrentReportingStatus" xlink:to="lab_dei_EntityCurrentReportingStatus" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_f61d983b-2d00-43ab-8b5e-a9b79515e6af_periodStartLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the beginning of the period </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_d12f7da4-4c96-4a92-9859-375441b9b4f2_periodEndLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the end of the period </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_cc5cb7ea-a684-4d58-aaba-f66331b3fc8c_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined benefit plan, plan assets </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_77de464b-f3bd-4753-aaac-0f9beda05f96_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value of plan assets </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations_751972f5-d29d-493f-a49e-54d433ec12b0_totalLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective tax rate </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LossContingencyEstimateOfPossibleLoss_18df4949-d201-4246-92ca-b58fcf280c72_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Estimate of possible loss </link:label>
<link:label id="lab_us-gaap_LossContingencyEstimateOfPossibleLoss_label_en-US" xlink:label="lab_us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency, Estimate of Possible Loss </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:to="lab_us-gaap_LossContingencyEstimateOfPossibleLoss" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CapitalizedCostToFulfillCustomerContractsMember_7a5e6e6b-23d1-49dd-b409-9cb84af9df03_terseLabel_en-US" xlink:label="lab_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Fulfill Customer Contracts </link:label>
<link:label id="lab_aon_CapitalizedCostToFulfillCustomerContractsMember_label_en-US" xlink:label="lab_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Fulfill Customer Contracts [Member] </link:label>
<link:label id="lab_aon_CapitalizedCostToFulfillCustomerContractsMember_documentation_en-US" xlink:label="lab_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Fulfill Customer Contracts [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:href="aon-20211231.xsd#aon_CapitalizedCostToFulfillCustomerContractsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:to="lab_aon_CapitalizedCostToFulfillCustomerContractsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_8db58a5e-aae4-4501-93c1-16fd101839c4_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected employer contributions during next fiscal year </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtCurrent_9616e0f4-9568-4d31-8e2b-08895614e7fe_terseLabel_en-US" xlink:label="lab_us-gaap_DebtCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term debt and current portion of long-term debt </link:label>
<link:label id="lab_us-gaap_DebtCurrent_455f5e1e-b8c3-4309-a12a-e8d34ae4c198_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtCurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Short-term debt and current portion of long-term debt </link:label>
<link:label id="lab_us-gaap_DebtCurrent_label_en-US" xlink:label="lab_us-gaap_DebtCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtCurrent" xlink:to="lab_us-gaap_DebtCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ContractWithCustomerAssetNetCurrent_b45ff31e-ae19-4ab5-b7a3-77a4daee8858_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNetCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Costs to fulfill contracts with customers </link:label>
<link:label id="lab_us-gaap_ContractWithCustomerAssetNetCurrent_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNetCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract with Customer, Asset, after Allowance for Credit Loss, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetNetCurrent" xlink:to="lab_us-gaap_ContractWithCustomerAssetNetCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_country_US_ca2cd0dd-9f28-4001-9c19-f5012585e17e_verboseLabel_en-US" xlink:label="lab_country_US" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. </link:label>
<link:label id="lab_country_US_35121da3-6618-4f5e-b633-380aae1969d0_terseLabel_en-US" xlink:label="lab_country_US" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. </link:label>
<link:label id="lab_country_US_label_en-US" xlink:label="lab_country_US" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> UNITED STATES </link:label>
<link:loc xlink:type="locator" xlink:label="loc_country_US" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_US"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_US" xlink:to="lab_country_US" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AmortizationAndImpairmentOfIntangibleAssets_007401d0-30b4-4c12-8baa-596307f02ecb_terseLabel_en-US" xlink:label="lab_aon_AmortizationAndImpairmentOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization and impairment of intangible assets </link:label>
<link:label id="lab_aon_AmortizationAndImpairmentOfIntangibleAssets_label_en-US" xlink:label="lab_aon_AmortizationAndImpairmentOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization And Impairment Of Intangible Assets </link:label>
<link:label id="lab_aon_AmortizationAndImpairmentOfIntangibleAssets_documentation_en-US" xlink:label="lab_aon_AmortizationAndImpairmentOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization And Impairment Of Intangible Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AmortizationAndImpairmentOfIntangibleAssets" xlink:href="aon-20211231.xsd#aon_AmortizationAndImpairmentOfIntangibleAssets"/>
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<link:label id="lab_us-gaap_LeasesAbstract_6046c0f9-7d5a-48c1-add2-430f90c96095_terseLabel_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases </link:label>
<link:label id="lab_us-gaap_LeasesAbstract_label_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases [Abstract] </link:label>
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<link:label id="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFundsHeldOnBehalfOfClient_7941e0af-2288-479a-9dd6-4f7a7623c008_terseLabel_en-US" xlink:label="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFundsHeldOnBehalfOfClient" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Funds held on behalf of client </link:label>
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<link:label id="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFundsHeldOnBehalfOfClient_documentation_en-US" xlink:label="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFundsHeldOnBehalfOfClient" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Funds Held On Behalf Of Client </link:label>
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<link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_38424853-7388-4bae-a207-ca78a128c900_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Taxes </link:label>
<link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:to="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_7c009571-c121-467c-beb7-f92cff44efac_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Income (Loss) [Line Items] </link:label>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Income (Loss) [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
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<link:label id="lab_us-gaap_DisposalGroupClassificationDomain_b4382360-b4af-4480-af09-750478d01252_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Classification [Domain] </link:label>
<link:label id="lab_us-gaap_DisposalGroupClassificationDomain_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Classification [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain" xlink:to="lab_us-gaap_DisposalGroupClassificationDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_d71e3142-ed33-4abb-858b-ccffe86332a4_negatedLabel_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts reclassified from accumulated other comprehensive income </link:label>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_label_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reclassification from AOCI, Current Period, before Tax, Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent"/>
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<link:label id="lab_dei_EntityAddressPostalZipCode_61732bbd-838b-464e-8847-5229107b5302_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Postal Zip Code </link:label>
<link:label id="lab_dei_EntityAddressPostalZipCode_label_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Postal Zip Code </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressPostalZipCode"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressPostalZipCode" xlink:to="lab_dei_EntityAddressPostalZipCode" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_fec11775-5a4e-46cb-a990-56b6681612d9_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue Recognition </link:label>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contract with Customer [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_0f5e63ab-b6a4-4f3b-83e5-f918a8aed538_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average ordinary shares outstanding - diluted (in shares) </link:label>
<link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_bfaa3381-66d1-46d1-89e1-05afaef89473_totalLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Diluted weighted average ordinary shares outstanding (in shares) </link:label>
<link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted Average Number of Shares Outstanding, Diluted </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
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<link:label id="lab_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_05511a27-4de4-4428-a974-9b2f7184858b_terseLabel_en-US" xlink:label="lab_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Error Corrections and Prior Period Adjustments Restatement [Line Items] </link:label>
<link:label id="lab_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_label_en-US" xlink:label="lab_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Error Corrections and Prior Period Adjustments Restatement [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems"/>
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<link:label id="lab_us-gaap_AdjustmentForAmortization_e02bde35-933c-44d6-a668-ad51aa821926_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentForAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization and impairment of intangible assets </link:label>
<link:label id="lab_us-gaap_AdjustmentForAmortization_label_en-US" xlink:label="lab_us-gaap_AdjustmentForAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentForAmortization"/>
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<link:label id="lab_us-gaap_IncomeTaxDisclosureTextBlock_15dce3b2-c8ef-4bc7-bb65-7f531fbce862_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Taxes </link:label>
<link:label id="lab_us-gaap_IncomeTaxDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Disclosure [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock"/>
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<link:label id="lab_us-gaap_LongtermDebtTypeAxis_d1c5c019-50f6-4682-b19e-e54110a76b03_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Type [Axis] </link:label>
<link:label id="lab_us-gaap_LongtermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Type [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
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<link:label id="lab_aon_CreditFacilityExpiringOctober2023Member_36729b3b-8333-4432-8ec9-119f71ec9ccf_terseLabel_en-US" xlink:label="lab_aon_CreditFacilityExpiringOctober2023Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring October 2023 </link:label>
<link:label id="lab_aon_CreditFacilityExpiringOctober2023Member_label_en-US" xlink:label="lab_aon_CreditFacilityExpiringOctober2023Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring October 2023 [Member] </link:label>
<link:label id="lab_aon_CreditFacilityExpiringOctober2023Member_documentation_en-US" xlink:label="lab_aon_CreditFacilityExpiringOctober2023Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring October 2023 [Member] </link:label>
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<link:label id="lab_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_4863c569-4808-4502-81a1-6262f9e04540_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Net Periodic Benefit Cost for the Pension Plans </link:label>
<link:label id="lab_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Net Benefit Costs [Table Text Block] </link:label>
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<link:label id="lab_us-gaap_DeferredTaxAssetsInvestments_c80f6220-c447-4442-9bb2-ea26371413da_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Investment basis differences </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsInvestments_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsInvestments" xlink:to="lab_us-gaap_DeferredTaxAssetsInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_36829283-eaca-4ecb-9781-32105c7c693d_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Cash Flows [Abstract] </link:label>
<link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Cash Flows [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseDiscountRate_39604ea4-fb52-4c7c-89f7-c35d3203d6b3_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating leases </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseDiscountRate_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Discount Rate </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseDiscountRate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:to="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A625SeniorNotesDueSeptember2040Member_7c8d7d70-0e96-4532-9fd4-bbb2afe1c7d1_terseLabel_en-US" xlink:label="lab_aon_A625SeniorNotesDueSeptember2040Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 6.25% Senior Notes due September 2040 </link:label>
<link:label id="lab_aon_A625SeniorNotesDueSeptember2040Member_label_en-US" xlink:label="lab_aon_A625SeniorNotesDueSeptember2040Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 6.25% Senior Notes Due September 2040 [Member] </link:label>
<link:label id="lab_aon_A625SeniorNotesDueSeptember2040Member_documentation_en-US" xlink:label="lab_aon_A625SeniorNotesDueSeptember2040Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> This element represents the senior notes that bear an interest rate of 6.25 percent and will mature in 2040. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A625SeniorNotesDueSeptember2040Member" xlink:href="aon-20211231.xsd#aon_A625SeniorNotesDueSeptember2040Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A625SeniorNotesDueSeptember2040Member" xlink:to="lab_aon_A625SeniorNotesDueSeptember2040Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OccupancyNet_833a2c8f-a5f4-480a-adc2-944146dc4305_terseLabel_en-US" xlink:label="lab_us-gaap_OccupancyNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Premises </link:label>
<link:label id="lab_us-gaap_OccupancyNet_label_en-US" xlink:label="lab_us-gaap_OccupancyNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Occupancy, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OccupancyNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OccupancyNet" xlink:to="lab_us-gaap_OccupancyNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NondesignatedMember_85d5ddc5-baed-4374-a892-5454ca65a88d_verboseLabel_en-US" xlink:label="lab_us-gaap_NondesignatedMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Not accounted for as hedges </link:label>
<link:label id="lab_us-gaap_NondesignatedMember_label_en-US" xlink:label="lab_us-gaap_NondesignatedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Not Designated as Hedging Instrument [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NondesignatedMember" xlink:to="lab_us-gaap_NondesignatedMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CreditFacilityAxis_6daf6dac-1127-4023-b50a-53747eab2228_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility [Axis] </link:label>
<link:label id="lab_us-gaap_CreditFacilityAxis_label_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityAxis" xlink:to="lab_us-gaap_CreditFacilityAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_496cd034-b209-432c-b38c-eaa093c341f6_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets, Major Class Name [Domain] </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets, Major Class Name [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityAddressAddressLine1_3d458acf-4423-4515-b506-3094bd3321eb_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Address Line One </link:label>
<link:label id="lab_dei_EntityAddressAddressLine1_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, Address Line One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressAddressLine1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine1" xlink:to="lab_dei_EntityAddressAddressLine1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RetirementPlanSponsorLocationDomain_ecd8ded1-bdde-4283-98e8-a17411e39391_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Sponsor Location [Domain] </link:label>
<link:label id="lab_us-gaap_RetirementPlanSponsorLocationDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Sponsor Location [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain" xlink:to="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_2c1368ec-3682-4cac-a300-01bf5bf3fd7f_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Accumulated depreciation </link:label>
<link:label id="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock_51f67dcd-2450-4946-b595-36ddfad1a2d8_terseLabel_en-US" xlink:label="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Information Related to the Company's Other Post-Retirement Benefit Plans </link:label>
<link:label id="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock_label_en-US" xlink:label="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Postretirement Benefits Other Information [Table Text Block] </link:label>
<link:label id="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock_documentation_en-US" xlink:label="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disclosure of the net periodic benefit cost recognized, weighted-average discount rate used to determine future benefit obligations and weighted-average discount rate used to determine net periodic benefit costs for the other post-retirement benefits plan. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:href="aon-20211231.xsd#aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:to="lab_aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_cca4e728-9501-4caa-ac1c-5d0f03706718_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other assets </link:label>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1512a4f3-2540-4b53-8a97-4f304d7237e3_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash flows from operating activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Operating Activities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_9c27df58-6c39-42f4-b02c-fd5c6f0a156d_terseLabel_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Principles of Consolidation </link:label>
<link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consolidation, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsolidationPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConsolidationPolicyTextBlock" xlink:to="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityShellCompany_04d25fa8-0348-434f-9f12-3c42b0a74c92_terseLabel_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Shell Company </link:label>
<link:label id="lab_dei_EntityShellCompany_label_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Shell Company </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityShellCompany"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityShellCompany" xlink:to="lab_dei_EntityShellCompany" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LiabilitiesCurrent_5a0adc62-28b0-4ec0-b600-f6b28c3409e5_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total current liabilities </link:label>
<link:label id="lab_us-gaap_LiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="lab_us-gaap_LiabilitiesCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_5447eecf-cc3e-4b3e-a1f5-7210658bcf8a_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Issuance of shares for employee benefit plans </link:label>
<link:label id="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payment, Tax Withholding, Share-based Payment Arrangement </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:to="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IntersegmentEliminationMember_24686626-1fb0-4c86-8b55-29a67b2f6e2c_terseLabel_en-US" xlink:label="lab_us-gaap_IntersegmentEliminationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Elimination </link:label>
<link:label id="lab_us-gaap_IntersegmentEliminationMember_label_en-US" xlink:label="lab_us-gaap_IntersegmentEliminationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Intersegment Eliminations [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntersegmentEliminationMember" xlink:to="lab_us-gaap_IntersegmentEliminationMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ReinsuranceSolutionsMember_8aded6c2-3843-4699-a7b2-8a5623205f5d_terseLabel_en-US" xlink:label="lab_aon_ReinsuranceSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reinsurance Solutions </link:label>
<link:label id="lab_aon_ReinsuranceSolutionsMember_label_en-US" xlink:label="lab_aon_ReinsuranceSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reinsurance Solutions [Member] </link:label>
<link:label id="lab_aon_ReinsuranceSolutionsMember_documentation_en-US" xlink:label="lab_aon_ReinsuranceSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reinsurance Solutions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ReinsuranceSolutionsMember" xlink:href="aon-20211231.xsd#aon_ReinsuranceSolutionsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ReinsuranceSolutionsMember" xlink:to="lab_aon_ReinsuranceSolutionsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LitigationStatusDomain_35cee6bb-81a9-41ce-9ed3-331170002207_terseLabel_en-US" xlink:label="lab_us-gaap_LitigationStatusDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Status [Domain] </link:label>
<link:label id="lab_us-gaap_LitigationStatusDomain_label_en-US" xlink:label="lab_us-gaap_LitigationStatusDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Status [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LitigationStatusDomain" xlink:to="lab_us-gaap_LitigationStatusDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LossContingenciesTable_0abb9d04-7648-4071-828e-0af87f070f5b_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingencies [Table] </link:label>
<link:label id="lab_us-gaap_LossContingenciesTable_label_en-US" xlink:label="lab_us-gaap_LossContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingencies [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesTable" xlink:to="lab_us-gaap_LossContingenciesTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_72b999c1-c2eb-4fac-948f-12b66e916fab_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents </link:label>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:type="arc" order="1"/>
<link:label id="lab_dei_CurrentFiscalYearEndDate_d4dd7faa-2926-4d3b-81bb-5a8a12e62317_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Fiscal Year End Date </link:label>
<link:label id="lab_dei_CurrentFiscalYearEndDate_label_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Fiscal Year End Date </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CurrentFiscalYearEndDate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CurrentFiscalYearEndDate" xlink:to="lab_dei_CurrentFiscalYearEndDate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_487f7732-8bc3-4050-83d2-b592a6622dde_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unamortized discounts, premiums, and debt issuance costs </link:label>
<link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:to="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LossContingencyNumberOfDefendants_5c9ac7fc-f66d-4d3b-b1d0-85c1cf42b8c1_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyNumberOfDefendants" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss contingency, number of defendants </link:label>
<link:label id="lab_us-gaap_LossContingencyNumberOfDefendants_label_en-US" xlink:label="lab_us-gaap_LossContingencyNumberOfDefendants" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency, Number of Defendants </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNumberOfDefendants" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNumberOfDefendants"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyNumberOfDefendants" xlink:to="lab_us-gaap_LossContingencyNumberOfDefendants" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementTable_ee87e3ab-fe05-4033-9fc6-a8d4a1630b37_terseLabel_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement [Table] </link:label>
<link:label id="lab_us-gaap_StatementTable_label_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementTable" xlink:to="lab_us-gaap_StatementTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_61999846-d68e-44c9-8db1-c87ccf5e4813_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plans with ABO in excess of the fair value of plan assets, ABO </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A3.75SeniorNotesDueMay22029Member_e0dfac3c-6a5c-48e4-ad32-25a3c1254cca_terseLabel_en-US" xlink:label="lab_aon_A3.75SeniorNotesDueMay22029Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.75% Senior Notes due May 2029 </link:label>
<link:label id="lab_aon_A3.75SeniorNotesDueMay22029Member_label_en-US" xlink:label="lab_aon_A3.75SeniorNotesDueMay22029Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.75% Senior Notes Due May 2, 2029 [Member] </link:label>
<link:label id="lab_aon_A3.75SeniorNotesDueMay22029Member_documentation_en-US" xlink:label="lab_aon_A3.75SeniorNotesDueMay22029Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.75% Senior Notes Due May 2, 2029 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A3.75SeniorNotesDueMay22029Member" xlink:href="aon-20211231.xsd#aon_A3.75SeniorNotesDueMay22029Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A3.75SeniorNotesDueMay22029Member" xlink:to="lab_aon_A3.75SeniorNotesDueMay22029Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_ab7dc559-2f3b-4aae-bcf7-2aea1b0c1b10_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> New Accounting Standards </link:label>
<link:label id="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> New Accounting Pronouncements, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20182020Member_21d00025-c8e2-4c8c-9f1b-d35159cbe836_terseLabel_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20182020Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2018-2020 </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20182020Member_label_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20182020Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2018-2020 [Member] </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20182020Member_documentation_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20182020Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2018-2020 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LeadershipPerformancePlanCycle20182020Member" xlink:href="aon-20211231.xsd#aon_LeadershipPerformancePlanCycle20182020Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LeadershipPerformancePlanCycle20182020Member" xlink:to="lab_aon_LeadershipPerformancePlanCycle20182020Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsOther_87b024fc-486f-42e5-a11a-d61f86b229c1_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsOther_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsOther"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsOther" xlink:to="lab_us-gaap_DeferredTaxAssetsOther" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_35b7cd70-c7bb-40de-8244-4abc4568cf1f_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable_18405180-a8b8-407d-864b-bf994161d144_terseLabel_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of shares that would be issued based on current performance levels (in shares) </link:label>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable_label_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share Based Compensation Arrangement by Share Based Payment Award Shares Issuable </link:label>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable_documentation_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the number of shares to be issued for performance-based stock award programs, based on the current performance levels. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:href="aon-20211231.xsd#aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:to="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_1658d971-d22e-4d03-bb93-8abb87a4acbb_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unamortized deferred compensation </link:label>
<link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="arc" order="1"/>
<link:label id="lab_srt_RangeAxis_af68a8a7-0c88-4581-abec-7d8eb695ec57_terseLabel_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statistical Measurement [Axis] </link:label>
<link:label id="lab_srt_RangeAxis_label_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statistical Measurement [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeAxis" xlink:to="lab_srt_RangeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy_b0890c64-7e75-447b-8099-6aa19f6e684c_terseLabel_en-US" xlink:label="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Allowance for Doubtful Accounts </link:label>
<link:label id="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy_label_en-US" xlink:label="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TradeAndOtherAccountsReceivablePolicy"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:to="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member_baa7a97f-f99a-4ff2-abb5-8bf835bd6b71_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 4.60% Senior Notes due 2044 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.600 Senior Notes Due 2044 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.600 Senior Notes Due 2044 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:to="lab_aon_GuaranteesOfAonPlcs4600SeniorNotesDue2044Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SubsequentEventMember_5527eabf-eb77-4d6b-b3dd-78fb2fb7b4fc_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event </link:label>
<link:label id="lab_us-gaap_SubsequentEventMember_label_en-US" xlink:label="lab_us-gaap_SubsequentEventMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventMember" xlink:to="lab_us-gaap_SubsequentEventMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrent_a36ede92-49e9-47a6-a9d2-3adf35f473d3_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases (2) </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrent_b23a74d3-0f6b-4b0d-b2d5-688b20afa234_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrent_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:to="lab_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_9a9fc450-1fd7-446c-b9ae-e3f1af0d4baa_totalLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_Goodwill_2cb55f93-3599-43d1-85f7-df62ca5d1be5_terseLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill </link:label>
<link:label id="lab_us-gaap_Goodwill_493b0fbb-7eac-439a-ab98-b23c482a8c50_periodStartLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the beginning of the period </link:label>
<link:label id="lab_us-gaap_Goodwill_758d2657-b013-4674-9a79-e6cc7ab82311_periodEndLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the end of the period </link:label>
<link:label id="lab_us-gaap_Goodwill_label_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Goodwill" xlink:to="lab_us-gaap_Goodwill" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember_e2668c42-c70f-4c4b-b846-2587dad05692_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Cash and Cash Equivalents [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:to="lab_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_MinorityInterest_b8066459-4853-4505-87f5-845f198ec1c7_terseLabel_en-US" xlink:label="lab_us-gaap_MinorityInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Noncontrolling interests </link:label>
<link:label id="lab_us-gaap_MinorityInterest_label_en-US" xlink:label="lab_us-gaap_MinorityInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stockholders' Equity Attributable to Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterest"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MinorityInterest" xlink:to="lab_us-gaap_MinorityInterest" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_ce671f06-b9ae-4069-ba2c-58c671fb54e4_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Taxes on international operations </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OperatingAndFinanceLeaseLiability_3b46b2e6-878e-4164-b721-5007e7e4ff4d_totalLabel_en-US" xlink:label="lab_aon_OperatingAndFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total lease liabilities </link:label>
<link:label id="lab_aon_OperatingAndFinanceLeaseLiability_label_en-US" xlink:label="lab_aon_OperatingAndFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating And Finance Lease Liability </link:label>
<link:label id="lab_aon_OperatingAndFinanceLeaseLiability_documentation_en-US" xlink:label="lab_aon_OperatingAndFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating And Finance Lease Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OperatingAndFinanceLeaseLiability" xlink:href="aon-20211231.xsd#aon_OperatingAndFinanceLeaseLiability"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OperatingAndFinanceLeaseLiability" xlink:to="lab_aon_OperatingAndFinanceLeaseLiability" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy_ef3cd528-4653-4782-988c-9eae42c410b9_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension and Other Post-Retirement Benefits </link:label>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy" xlink:to="lab_us-gaap_PensionAndOtherPostretirementPlansPensionsPolicy" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfGoodwillTextBlock_8892b967-9e9f-4caf-b54b-b6f8e23cef2d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Changes in the Net Carrying Amount of Goodwill by Operating Segment </link:label>
<link:label id="lab_us-gaap_ScheduleOfGoodwillTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Goodwill [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfGoodwillTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfGoodwillTextBlock" xlink:to="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_a8739fc8-671e-49d5-a53d-329335a313d3_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Adjustments to reconcile net income to cash provided by operating activities:            </link:label>
<link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsForRepurchaseOfEquityAbstract_ac193af0-7fc5-4b39-9903-c98d3b3d6dd1_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Costs recorded to retained earnings </link:label>
<link:label id="lab_us-gaap_PaymentsForRepurchaseOfEquityAbstract_label_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments for Repurchase of Equity [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquityAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForRepurchaseOfEquityAbstract" xlink:to="lab_us-gaap_PaymentsForRepurchaseOfEquityAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ApolloConseilEtCourtageMember_96a918f4-df60-4fca-9a27-9e31acebc0d8_terseLabel_en-US" xlink:label="lab_aon_ApolloConseilEtCourtageMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Apollo Conseilet Courtage </link:label>
<link:label id="lab_aon_ApolloConseilEtCourtageMember_label_en-US" xlink:label="lab_aon_ApolloConseilEtCourtageMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Apollo Conseil et Courtage [Member] </link:label>
<link:label id="lab_aon_ApolloConseilEtCourtageMember_documentation_en-US" xlink:label="lab_aon_ApolloConseilEtCourtageMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Apollo Conseil et Courtage </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ApolloConseilEtCourtageMember" xlink:href="aon-20211231.xsd#aon_ApolloConseilEtCourtageMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ApolloConseilEtCourtageMember" xlink:to="lab_aon_ApolloConseilEtCourtageMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SubsequentEventTypeAxis_f33cf4a4-10fe-4e7a-8afb-b9e4e32507b5_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event Type [Axis] </link:label>
<link:label id="lab_us-gaap_SubsequentEventTypeAxis_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Subsequent Event Type [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTypeAxis" xlink:to="lab_us-gaap_SubsequentEventTypeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseCost_9eca32b9-6ce8-4177-b34b-e1eb4bf31c55_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating lease cost </link:label>
<link:label id="lab_us-gaap_OperatingLeaseCost_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseCost" xlink:to="lab_us-gaap_OperatingLeaseCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComputerEquipmentMember_2a4e2c1e-cf12-4ead-b162-e754fefb0b6c_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Computer equipment </link:label>
<link:label id="lab_us-gaap_ComputerEquipmentMember_label_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Computer Equipment [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComputerEquipmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComputerEquipmentMember" xlink:to="lab_us-gaap_ComputerEquipmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanDerivativeMember_404c8f45-45dc-4fca-9175-99b371573f10_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDerivativeMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivatives </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanDerivativeMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDerivativeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Derivative [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDerivativeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanDerivativeMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanDerivativeMember" xlink:to="lab_us-gaap_DefinedBenefitPlanDerivativeMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_9a4f4f1e-3de8-4280-8e5c-48e3cf395e34_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Post-retirement Benefit Obligations </link:label>
<link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:to="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EmployeeStockPurchasePlansAndOtherMember_75f54392-2d81-441b-8c85-cdc580145b35_terseLabel_en-US" xlink:label="lab_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee share purchase plans and other </link:label>
<link:label id="lab_aon_EmployeeStockPurchasePlansAndOtherMember_label_en-US" xlink:label="lab_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee Stock Purchase Plans And Other [Member] </link:label>
<link:label id="lab_aon_EmployeeStockPurchasePlansAndOtherMember_documentation_en-US" xlink:label="lab_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee Stock Purchase Plans And Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:href="aon-20211231.xsd#aon_EmployeeStockPurchasePlansAndOtherMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:to="lab_aon_EmployeeStockPurchasePlansAndOtherMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_776008a4-11c7-4235-8fef-bfb065bb4144_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total deferred tax expense (benefit) </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Tax Expense (Benefit) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AutomobilesMember_193a21bd-eb28-4842-9e0b-769f5528c804_terseLabel_en-US" xlink:label="lab_us-gaap_AutomobilesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Automobiles </link:label>
<link:label id="lab_us-gaap_AutomobilesMember_label_en-US" xlink:label="lab_us-gaap_AutomobilesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Automobiles [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AutomobilesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AutomobilesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AutomobilesMember" xlink:to="lab_us-gaap_AutomobilesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_58354acf-5171-40f9-b716-af362d88f649_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ordinary Shares and Additional Paid-in Capital </link:label>
<link:label id="lab_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_label_en-US" xlink:label="lab_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock Including Additional Paid in Capital [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember" xlink:to="lab_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany_311af721-9c45-4c22-b061-8da418d57117_terseLabel_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (decrease) in operating funds required to be held by the company </link:label>
<link:label id="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany_label_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) In Operating Funds Required To Be Held By Company </link:label>
<link:label id="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany_documentation_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) In Operating Funds Required To Be Held By Company </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:href="aon-20211231.xsd#aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:to="lab_aon_IncreaseDecreaseInOperatingFundsRequiredToBeHeldByCompany" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EmployeerelatedLiabilitiesNoncurrent_39214cfa-2f8a-4189-98e2-725c327c9e66_terseLabel_en-US" xlink:label="lab_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation and benefits </link:label>
<link:label id="lab_aon_EmployeerelatedLiabilitiesNoncurrent_label_en-US" xlink:label="lab_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee-related Liabilities, Noncurrent </link:label>
<link:label id="lab_aon_EmployeerelatedLiabilitiesNoncurrent_documentation_en-US" xlink:label="lab_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee-related Liabilities, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:href="aon-20211231.xsd#aon_EmployeerelatedLiabilitiesNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:to="lab_aon_EmployeerelatedLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_HedgingDesignationDomain_e3515a92-b615-480a-a38c-53106faf6966_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Designation [Domain] </link:label>
<link:label id="lab_us-gaap_HedgingDesignationDomain_label_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Designation [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingDesignationDomain" xlink:to="lab_us-gaap_HedgingDesignationDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1_b0216899-765d-4b25-8f44-ff7645fa93d8_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share repurchase authorization amount </link:label>
<link:label id="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1_label_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stock Repurchase Program, Authorized Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:to="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_835b2f55-1c52-4b73-8a58-1c641329d0ff_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statutory tax rate </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_0f2d0b33-4987-4fde-8a24-bf223e004e0f_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Earnings per Share </link:label>
<link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Earnings Per Share, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bcaa307-7b0f-4a70-bab8-5af69e3725ac_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Hierarchy and NAV [Domain] </link:label>
<link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Hierarchy and NAV [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation_55215547-b812-462e-bce4-94c2c13ca4e7_terseLabel_en-US" xlink:label="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Underlying price inflation </link:label>
<link:label id="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation_label_en-US" xlink:label="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Underlying Price Inflation </link:label>
<link:label id="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation_documentation_en-US" xlink:label="lab_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Underlying Price Inflation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" xlink:href="aon-20211231.xsd#aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation"/>
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<link:label id="lab_us-gaap_NetIncomeLoss_9a0518dd-c0c5-4f23-92dd-bfa5849baa13_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net income attributable to Aon shareholders </link:label>
<link:label id="lab_us-gaap_NetIncomeLoss_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Income (Loss) Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CapitalizedContractCostAdditions_3c4c7609-7039-43f2-808c-c3638c2930e3_terseLabel_en-US" xlink:label="lab_aon_CapitalizedContractCostAdditions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additions </link:label>
<link:label id="lab_aon_CapitalizedContractCostAdditions_label_en-US" xlink:label="lab_aon_CapitalizedContractCostAdditions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Additions </link:label>
<link:label id="lab_aon_CapitalizedContractCostAdditions_documentation_en-US" xlink:label="lab_aon_CapitalizedContractCostAdditions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Additions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CapitalizedContractCostAdditions" xlink:href="aon-20211231.xsd#aon_CapitalizedContractCostAdditions"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CapitalizedContractCostAdditions" xlink:to="lab_aon_CapitalizedContractCostAdditions" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_961a1c7e-14fb-47eb-8038-5975ffdc9076_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating lease right-of-use assets </link:label>
<link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_e3efb86a-3a6a-412e-972c-8af158b863fd_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating lease assets </link:label>
<link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Right-of-Use Asset </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:to="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_c774689f-e632-4035-a2f1-5aafad9122fd_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Notional and Fair Values of Derivative Instruments </link:label>
<link:label id="lab_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNotionalAmountsOfOutstandingDerivativePositionsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanInterestCost_3a01aa5f-8d31-41db-9c72-76121e6822e9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest cost </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanInterestCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Interest Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanInterestCost" xlink:to="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeStatementLocationAxis_0bac97da-7b44-42ee-809b-7e4f221dcf79_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Statement Location [Axis] </link:label>
<link:label id="lab_us-gaap_IncomeStatementLocationAxis_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Statement Location [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationAxis" xlink:to="lab_us-gaap_IncomeStatementLocationAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_a96a9372-42a8-48c7-8dbe-50a51614d8da_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Amortization and Impairment </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets, Accumulated Amortization </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="arc" order="1"/>
<link:label id="lab_srt_RangeMember_b4e8757b-5d13-43ea-8ea7-f49b7efe4807_terseLabel_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statistical Measurement [Domain] </link:label>
<link:label id="lab_srt_RangeMember_label_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statistical Measurement [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeMember" xlink:to="lab_srt_RangeMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_d9a65fe6-c1fd-4ab6-8276-c08874c39ac8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Repayments of Long-term Debt </link:label>
<link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Maturities of Long-term Debt [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityIncorporationStateCountryCode_4f3253b1-eb33-4013-a14b-a0dbf5e45891_terseLabel_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Incorporation, State or Country Code </link:label>
<link:label id="lab_dei_EntityIncorporationStateCountryCode_label_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Incorporation, State or Country Code </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityIncorporationStateCountryCode"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationStateCountryCode" xlink:to="lab_dei_EntityIncorporationStateCountryCode" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerAbstract_9a976f07-97ba-4fd7-ba25-0488ce064ac2_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contract with Customer [Abstract] </link:label>
<link:label id="lab_us-gaap_RevenueFromContractWithCustomerAbstract_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenue from Contract with Customer [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_183f8ee7-938b-4f69-aff8-8df43c6bbba8_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additional paid-in capital </link:label>
<link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Additional Paid in Capital, Common Stock </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:to="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAssetsNoncurrent_6bafac60-3e34-489d-9edc-e3ba3d83a5a4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other non-current assets </link:label>
<link:label id="lab_us-gaap_OtherAssetsNoncurrent_624a739f-477d-49fe-b026-f3eafd44e193_totalLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_OtherAssetsNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Assets, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent" xlink:to="lab_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NumberOfBusinessesAcquired_008511d4-00d6-45c4-a4ae-e0d5170a57d0_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfBusinessesAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of business acquired under business combination </link:label>
<link:label id="lab_us-gaap_NumberOfBusinessesAcquired_label_en-US" xlink:label="lab_us-gaap_NumberOfBusinessesAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Businesses Acquired </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfBusinessesAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfBusinessesAcquired"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfBusinessesAcquired" xlink:to="lab_us-gaap_NumberOfBusinessesAcquired" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_cdda3111-e4e6-4de3-8fd2-0750a1bd4365_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected return on plan assets, net of administration expenses </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Return (Loss) on Plan Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CompensationAndRetirementDisclosureAbstract_f7fc1436-89ff-4864-8939-dcf64d9902fd_terseLabel_en-US" xlink:label="lab_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Benefits [Abstract] </link:label>
<link:label id="lab_us-gaap_CompensationAndRetirementDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Benefits [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract"/>
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<link:label id="lab_aon_LeadershipPerformancePlanCycle20172019Member_cdc940ce-f986-4e93-9b8e-310f48cc9fb6_terseLabel_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20172019Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2017-2019 </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20172019Member_label_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20172019Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2017-2019 [Member] </link:label>
<link:label id="lab_aon_LeadershipPerformancePlanCycle20172019Member_documentation_en-US" xlink:label="lab_aon_LeadershipPerformancePlanCycle20172019Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leadership Performance Plan Cycle 2017-2019 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LeadershipPerformancePlanCycle20172019Member" xlink:href="aon-20211231.xsd#aon_LeadershipPerformancePlanCycle20172019Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LeadershipPerformancePlanCycle20172019Member" xlink:to="lab_aon_LeadershipPerformancePlanCycle20172019Member" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityFileNumber_f6433846-5640-4768-88b8-cfd19ac2bdee_terseLabel_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity File Number </link:label>
<link:label id="lab_dei_EntityFileNumber_label_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity File Number </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFileNumber"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFileNumber" xlink:to="lab_dei_EntityFileNumber" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock_2e977c08-2420-47a9-a282-c628f21861ad_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Other Income </link:label>
<link:label id="lab_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Nonoperating Income (Expense) [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_0cfcc5c6-51ad-4f0b-82cb-f94591ca6711_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based compensation expense </link:label>
<link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> APIC, Share-based Payment Arrangement, Increase for Cost Recognition </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CapitalizedCostToObtainCustomerContractsMember_0be16d38-0674-4aed-906f-a47dd3992482_terseLabel_en-US" xlink:label="lab_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Obtain Customer Contracts </link:label>
<link:label id="lab_aon_CapitalizedCostToObtainCustomerContractsMember_label_en-US" xlink:label="lab_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Obtain Customer Contracts [Member] </link:label>
<link:label id="lab_aon_CapitalizedCostToObtainCustomerContractsMember_documentation_en-US" xlink:label="lab_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Cost To Obtain Customer Contracts [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:href="aon-20211231.xsd#aon_CapitalizedCostToObtainCustomerContractsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:to="lab_aon_CapitalizedCostToObtainCustomerContractsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments_9242e755-97d5-44c7-ae69-b24d4ba59423_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Proceeds from investments </link:label>
<link:label id="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Proceeds from Sale and Maturity of Other Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:to="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_aon_IncomeTaxHolidayIncomeTaxBenefits_0b38ed67-a5d2-41ca-be6f-8cc2c83cf7d4_terseLabel_en-US" xlink:label="lab_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Benefit realized from tax holiday granted </link:label>
<link:label id="lab_aon_IncomeTaxHolidayIncomeTaxBenefits_label_en-US" xlink:label="lab_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Holiday Income Tax Benefits </link:label>
<link:label id="lab_aon_IncomeTaxHolidayIncomeTaxBenefits_documentation_en-US" xlink:label="lab_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the income tax benefit resulting from the income tax holidays granted by taxing jurisdictions. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:href="aon-20211231.xsd#aon_IncomeTaxHolidayIncomeTaxBenefits"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:to="lab_aon_IncomeTaxHolidayIncomeTaxBenefits" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AonIndiaInsuranceBrokersLimitedMember_89d1b6d7-0873-41be-b881-18ad1b979353_terseLabel_en-US" xlink:label="lab_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon India Insurance Brokers Limited </link:label>
<link:label id="lab_aon_AonIndiaInsuranceBrokersLimitedMember_label_en-US" xlink:label="lab_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon India Insurance Brokers Limited [Member] </link:label>
<link:label id="lab_aon_AonIndiaInsuranceBrokersLimitedMember_documentation_en-US" xlink:label="lab_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aon India Insurance Brokers Limited </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:href="aon-20211231.xsd#aon_AonIndiaInsuranceBrokersLimitedMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:to="lab_aon_AonIndiaInsuranceBrokersLimitedMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_302628da-180a-42d1-a663-26ec47b0baaf_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Organization, Consolidation and Presentation of Financial Statements [Abstract] </link:label>
<link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Organization, Consolidation and Presentation of Financial Statements [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherCurrentAssetsMember_4e237401-4d51-4970-8f06-22ddab183225_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCurrentAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Current Assets </link:label>
<link:label id="lab_us-gaap_OtherCurrentAssetsMember_label_en-US" xlink:label="lab_us-gaap_OtherCurrentAssetsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Current Assets [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentAssetsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCurrentAssetsMember" xlink:to="lab_us-gaap_OtherCurrentAssetsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_VariableLeaseCost_7d015a1a-3ccb-426d-93cb-162b5f448f46_terseLabel_en-US" xlink:label="lab_us-gaap_VariableLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Variable lease cost </link:label>
<link:label id="lab_us-gaap_VariableLeaseCost_label_en-US" xlink:label="lab_us-gaap_VariableLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Variable Lease, Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableLeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableLeaseCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableLeaseCost" xlink:to="lab_us-gaap_VariableLeaseCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits_ec02da7b-ff2c-4660-a53c-d31209bfcdd4_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee benefit plans </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits" xlink:to="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BuildingMember_671a1dae-0721-485e-ab89-9aa6c0aa67b1_terseLabel_en-US" xlink:label="lab_us-gaap_BuildingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Buildings </link:label>
<link:label id="lab_us-gaap_BuildingMember_label_en-US" xlink:label="lab_us-gaap_BuildingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Building [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BuildingMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BuildingMember" xlink:to="lab_us-gaap_BuildingMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_505715c5-5fed-4884-8cfd-15e234cdc416_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Granted (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_36504193-e2f7-45b9-918c-b75259f32f7d_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_555d7cc6-c138-416a-93d8-bcef7039f3fe_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value of RSUs vested during the period </link:label>
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<link:label id="lab_us-gaap_CreditFacilityDomain_c28ebe11-300d-4072-8eca-66c0f8b3db51_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility [Domain] </link:label>
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<link:label id="lab_us-gaap_AssetsAbstract_056bdf15-847c-47b2-8bb9-b08b66386929_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets </link:label>
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<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_c8b04d4d-f02e-48e7-8122-ca7c7f12cfc8_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
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<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_286fd2e2-68b3-4f53-b9e7-bd6a6bf47667_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Discount rate </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_158af891-0a15-4547-94cb-ed3ac17ef1b5_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted-average discount rate used to determine future benefit obligations </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate </link:label>
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<link:label id="lab_us-gaap_TradeNamesMember_6b30cf3c-71cd-4a69-8a07-acf9701ad2a9_terseLabel_en-US" xlink:label="lab_us-gaap_TradeNamesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tradenames </link:label>
<link:label id="lab_us-gaap_TradeNamesMember_label_en-US" xlink:label="lab_us-gaap_TradeNamesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Trade Names [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TradeNamesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TradeNamesMember" xlink:to="lab_us-gaap_TradeNamesMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionTwo_1caf289b-b20f-4824-91e6-679063719239_terseLabel_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Damages sought option 2 </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionTwo_label_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option Two </link:label>
<link:label id="lab_aon_LossContingencyDamagesSoughtValueOptionTwo_documentation_en-US" xlink:label="lab_aon_LossContingencyDamagesSoughtValueOptionTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingency Damages Sought Value Option Two </link:label>
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<link:label id="lab_us-gaap_DebtInstrumentAxis_2e21e191-bae6-4fcf-98b8-ac34e87c7152_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument [Axis] </link:label>
<link:label id="lab_us-gaap_DebtInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentAxis" xlink:to="lab_us-gaap_DebtInstrumentAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_902d16d7-64d6-4fb1-ae41-309c396ae13b_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Claims, Lawsuits, and Other Contingencies </link:label>
<link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commitments and Contingencies Disclosure [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:to="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NumberOfDispositions_90c4dd95-9076-4cb2-bbe9-a8fafb77005c_terseLabel_en-US" xlink:label="lab_aon_NumberOfDispositions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of dispositions </link:label>
<link:label id="lab_aon_NumberOfDispositions_label_en-US" xlink:label="lab_aon_NumberOfDispositions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Dispositions </link:label>
<link:label id="lab_aon_NumberOfDispositions_documentation_en-US" xlink:label="lab_aon_NumberOfDispositions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the number of entities disposed of by the reporting entity. </link:label>
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<link:label id="lab_aon_OtherGeneralExpenses_2ac31d03-0378-40d9-b5cf-89032f62db33_terseLabel_en-US" xlink:label="lab_aon_OtherGeneralExpenses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other general expense </link:label>
<link:label id="lab_aon_OtherGeneralExpenses_label_en-US" xlink:label="lab_aon_OtherGeneralExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other General Expenses </link:label>
<link:label id="lab_aon_OtherGeneralExpenses_documentation_en-US" xlink:label="lab_aon_OtherGeneralExpenses" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> General recurring costs associated with normal operations, excluding compensation and benefits. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OtherGeneralExpenses" xlink:href="aon-20211231.xsd#aon_OtherGeneralExpenses"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OtherGeneralExpenses" xlink:to="lab_aon_OtherGeneralExpenses" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_6ebd8201-043f-4e43-be11-924662d01970_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization of prior-service cost </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Amortization of Prior Service Cost (Credit) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:to="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CompensationandBenefitsMember_e8f53ee9-d45b-476a-aa9d-b5da16c7ac5b_terseLabel_en-US" xlink:label="lab_aon_CompensationandBenefitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation and benefits </link:label>
<link:label id="lab_aon_CompensationandBenefitsMember_label_en-US" xlink:label="lab_aon_CompensationandBenefitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation and Benefits [Member] </link:label>
<link:label id="lab_aon_CompensationandBenefitsMember_documentation_en-US" xlink:label="lab_aon_CompensationandBenefitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation and Benefits [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CompensationandBenefitsMember" xlink:href="aon-20211231.xsd#aon_CompensationandBenefitsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CompensationandBenefitsMember" xlink:to="lab_aon_CompensationandBenefitsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions_567c1e5f-b0f3-4ae6-a2f7-5fcd7a146e9f_terseLabel_en-US" xlink:label="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Federal and state benefit of interest from uncertain tax positions </link:label>
<link:label id="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions_label_en-US" xlink:label="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Federal And State Benefit Of Interest From Uncertain Tax Positions </link:label>
<link:label id="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions_documentation_en-US" xlink:label="lab_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Federal And State Benefit Of Interest From Uncertain Tax Positions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions" xlink:href="aon-20211231.xsd#aon_DeferredTaxAssetsFederalAndStateBenefitOfInterestFromUncertainTaxPositions"/>
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<link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_ac1b39ac-82da-4f55-b690-63a1a4206718_terseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> ROU assets obtained in exchange for new operating lease liabilities </link:label>
<link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Right-of-Use Asset Obtained in Exchange for Operating Lease Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
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<link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_a4a79713-faa1-4caf-8bd1-564ec482a199_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Aon's Deferred Tax Assets and Liabilities </link:label>
<link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Deferred Tax Assets and Liabilities [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock"/>
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<link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_ffd77528-5bf0-4c88-beac-c02307a3d6fc_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commitments and Contingencies Disclosure [Abstract] </link:label>
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<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_45519ab1-1138-4623-8321-17f90a965693_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Target allocation percentage </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Target Allocation, Percentage </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>
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<link:label id="lab_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember_e5eb649c-5481-492f-93a2-61423adeea3e_terseLabel_en-US" xlink:label="lab_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period, Reclassification, Adjustment </link:label>
<link:label id="lab_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember_label_en-US" xlink:label="lab_srt_RevisionOfPriorPeriodReclassificationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revision of Prior Period, Reclassification, Adjustment [Member] </link:label>
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<link:label id="lab_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_8e92bcf0-4cac-4852-9adc-7300f6247962_terseLabel_en-US" xlink:label="lab_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Non-current Liabilities </link:label>
<link:label id="lab_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Noncurrent Liabilities [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:to="lab_us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock_08a76aea-5689-4df5-9a99-da7da3ce88d0_terseLabel_en-US" xlink:label="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Projected Benefit Obligations Fair Value of Plan Assets, Funded Status and Amount Recognized </link:label>
<link:label id="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock"/>
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<link:label id="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract_a4b0f91b-e2ac-4e4c-8158-fe91e8e97447_terseLabel_en-US" xlink:label="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average remaining lease term (years) </link:label>
<link:label id="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract_label_en-US" xlink:label="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Weighted-average Remaining Lease Term [Abstract] </link:label>
<link:label id="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract_documentation_en-US" xlink:label="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Weighted-average Remaining Lease Term [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:href="aon-20211231.xsd#aon_LesseeWeightedaverageRemainingLeaseTermAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:to="lab_aon_LesseeWeightedaverageRemainingLeaseTermAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_42bfb9fd-5dcd-443d-b9dc-018ec4df2bfc_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of credit facility, available credit </link:label>
<link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility, Remaining Borrowing Capacity </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NumberOfOperatingSegments_93632d21-0ca7-4ddd-9c86-1d2488cd2457_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfOperatingSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of operating segment </link:label>
<link:label id="lab_us-gaap_NumberOfOperatingSegments_label_en-US" xlink:label="lab_us-gaap_NumberOfOperatingSegments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Operating Segments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfOperatingSegments" xlink:to="lab_us-gaap_NumberOfOperatingSegments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GainLossOnSaleOfBusiness_e1dd2c5c-ee12-4dcf-8766-6a8a544a309d_negatedLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfBusiness" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain from sales of businesses and investments </link:label>
<link:label id="lab_us-gaap_GainLossOnSaleOfBusiness_63fecccd-b18d-4a72-acdf-981aeb8f3bf7_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain from disposal of business </link:label>
<link:label id="lab_us-gaap_GainLossOnSaleOfBusiness_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfBusiness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (Loss) on Disposition of Business </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
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<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_b0aef448-9375-451b-9349-d03ea43a3fbd_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Postretirement benefit obligation </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_1185aaf7-d115-4834-b649-1de9d17c9c2a_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net postretirement benefit obligation </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
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<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_3cdcb148-75d8-4af9-93f3-325683eb4d3f_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, Year Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_de7b1aad-79fb-409a-94a9-65c101264dcd_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Thereafter </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Expected Amortization, after Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PrepaidExpenseCurrent_29d9e6e5-3e92-4ca7-b8f6-117899377c34_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Prepaid expenses </link:label>
<link:label id="lab_us-gaap_PrepaidExpenseCurrent_label_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Prepaid Expense, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseCurrent" xlink:to="lab_us-gaap_PrepaidExpenseCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisaggregationOfRevenueTableTextBlock_aeeb61f7-4c93-4ffa-9a80-9bd4e2867d8c_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue </link:label>
<link:label id="lab_us-gaap_DisaggregationOfRevenueTableTextBlock_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:to="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_7c067562-7c83-48b4-a5ed-06579297b65e_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Term Debt, Maturity, Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
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<link:label id="lab_us-gaap_DefinedContributionPlanCostRecognized_0aab8d61-6a47-4139-8702-58150610afdc_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expense recognized for defined contribution savings plans </link:label>
<link:label id="lab_us-gaap_DefinedContributionPlanCostRecognized_label_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Contribution Plan, Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedContributionPlanCostRecognized" xlink:to="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_a810db53-0d74-4dec-b5c7-f7c30cf4e420_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-vested share awards </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
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<link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_fd97f23e-4675-445a-b7d4-671307093bf1_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Restricted Share Unit Activity </link:label>
<link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Nonvested Share Activity [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_InvestmentIncomeInterestAndDividend_4c307234-f304-4160-80ce-5b7ceac14c16_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentIncomeInterestAndDividend" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest income </link:label>
<link:label id="lab_us-gaap_InvestmentIncomeInterestAndDividend_label_en-US" xlink:label="lab_us-gaap_InvestmentIncomeInterestAndDividend" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Investment Income, Interest and Dividend </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterestAndDividend" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentIncomeInterestAndDividend"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentIncomeInterestAndDividend" xlink:to="lab_us-gaap_InvestmentIncomeInterestAndDividend" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeasePayments_dc13f931-fbfc-456d-a18b-36404d597bb3_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating cash flows for operating leases </link:label>
<link:label id="lab_us-gaap_OperatingLeasePayments_label_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Payments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasePayments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasePayments" xlink:to="lab_us-gaap_OperatingLeasePayments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_cb0f29c5-4a45-47f7-9faf-63360e235e61_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentOtherTypesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentOtherTypesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Other Types [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOtherTypesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentOtherTypesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferred1_c6f64ab0-bbce-499a-9c5d-9a5193138b39_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consideration transferred </link:label>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferred1_c242c1db-e1d6-4d06-a8be-cea41cbfd1fe_totalLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aggregate consideration transferred </link:label>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferred1_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Consideration Transferred </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:to="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_ee3dd60e-f662-48d2-98a4-7efcc0c95d85_terseLabel_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Provision </link:label>
<link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_label_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Credit Loss Expense (Reversal) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProvisionForDoubtfulAccounts" xlink:to="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_f3b6b57d-7a1c-4609-b26b-8883094b4ce3_totalLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total Repayments </link:label>
<link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Gross </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:to="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GoodwillRollForward_1bb6bbc8-1f18-479b-815d-7be7f6dac7ee_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill [Roll Forward] </link:label>
<link:label id="lab_us-gaap_GoodwillRollForward_label_en-US" xlink:label="lab_us-gaap_GoodwillRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillRollForward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillRollForward" xlink:to="lab_us-gaap_GoodwillRollForward" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized_151333fd-d01c-4746-919f-cc434b2ae7fa_terseLabel_en-US" xlink:label="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred revenue recognized </link:label>
<link:label id="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized_label_en-US" xlink:label="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract With Customer, Liability, Including New Contract Revenue, Recognized </link:label>
<link:label id="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized_documentation_en-US" xlink:label="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract With Customer, Liability, Including New Contract Revenue, Recognized </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:href="aon-20211231.xsd#aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:to="lab_aon_ContractWithCustomerLiabilityIncludingNewContractRevenueRecognized" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A3.875SeniorNotesdueDecember2025Member_34eaaf02-f8f1-480c-860a-8a71740e87bc_terseLabel_en-US" xlink:label="lab_aon_A3.875SeniorNotesdueDecember2025Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.875% Senior Notes due December 2025 </link:label>
<link:label id="lab_aon_A3.875SeniorNotesdueDecember2025Member_label_en-US" xlink:label="lab_aon_A3.875SeniorNotesdueDecember2025Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.875% Senior Notes due December 2025 [Member] </link:label>
<link:label id="lab_aon_A3.875SeniorNotesdueDecember2025Member_documentation_en-US" xlink:label="lab_aon_A3.875SeniorNotesdueDecember2025Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 3.875% Senior Notes due December 2025 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A3.875SeniorNotesdueDecember2025Member" xlink:href="aon-20211231.xsd#aon_A3.875SeniorNotesdueDecember2025Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A3.875SeniorNotesdueDecember2025Member" xlink:to="lab_aon_A3.875SeniorNotesdueDecember2025Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_470641e3-91f7-45e9-a00f-bca06587931e_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases </link:label>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_45ed3486-b184-4128-be55-3f8f48349248_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance lease assets </link:label>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Right-of-Use Asset, after Accumulated Amortization </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward_d8ead3cc-e66b-4c62-8761-b2877cab1376_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of the Company's beginning and ending amount of unrecognized tax benefits </link:label>
<link:label id="lab_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:to="lab_us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShorttermDebtAverageOutstandingAmount_ec52d3a3-9676-4d17-8b30-a2f29a9d2162_terseLabel_en-US" xlink:label="lab_us-gaap_ShorttermDebtAverageOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average commercial paper outstanding </link:label>
<link:label id="lab_us-gaap_ShorttermDebtAverageOutstandingAmount_label_en-US" xlink:label="lab_us-gaap_ShorttermDebtAverageOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Average Outstanding Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtAverageOutstandingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShorttermDebtAverageOutstandingAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShorttermDebtAverageOutstandingAmount" xlink:to="lab_us-gaap_ShorttermDebtAverageOutstandingAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_3f8d3298-2a11-46b5-b9df-a0ed964c71cf_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income tax expense: </link:label>
<link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Expense (Benefit), Continuing Operations [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_e1097109-1aba-458e-9cb1-1929f5a9f190_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total liabilities and equity </link:label>
<link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities and Equity </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_bad0c62d-bbdb-4c10-ad7c-139a4360def0_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other — net </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Other Adjustments, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_74229f4d-c0e4-4395-a330-7cc57898a3a3_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Accrued Liabilities, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ContractWithCustomerLiabilityCurrent_083aa8d4-0066-41b5-b541-645e1d674f1b_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred revenue </link:label>
<link:label id="lab_us-gaap_ContractWithCustomerLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract with Customer, Liability, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiabilityCurrent" xlink:to="lab_us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_775df8f0-ab0d-404e-8231-aedcce175990_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax_b2507ae7-b043-4b8d-aae4-e191d9d315a2_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrealized gain (loss) related to assets and liabilities measured at fair value using unobservable inputs </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_325865cf-a5aa-48b1-ba21-ca0697db5c72_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Benefit payments </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Benefits Paid </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_8683af9d-20f8-40ea-a0ad-d46fb4ef9fb7_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value at Date of Grant </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements_ff5b1535-f222-4ebf-8321-f6ff03ceb0a1_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Purchases, sales and settlements-net </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements" xlink:to="lab_us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlements" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeLineItems_bf61c765-3bbf-4e2f-814b-f109bb7a5cfb_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative [Line Items] </link:label>
<link:label id="lab_us-gaap_DerivativeLineItems_label_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLineItems" xlink:to="lab_us-gaap_DerivativeLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AviationandAerospaceBrokingIndustryMember_a70f2cd7-aea1-4219-b076-fea0d87685c4_terseLabel_en-US" xlink:label="lab_aon_AviationandAerospaceBrokingIndustryMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aviation and Aerospace Broking Industry </link:label>
<link:label id="lab_aon_AviationandAerospaceBrokingIndustryMember_label_en-US" xlink:label="lab_aon_AviationandAerospaceBrokingIndustryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aviation and Aerospace Broking Industry [Member] </link:label>
<link:label id="lab_aon_AviationandAerospaceBrokingIndustryMember_documentation_en-US" xlink:label="lab_aon_AviationandAerospaceBrokingIndustryMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Aviation and Aerospace Broking Industry [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AviationandAerospaceBrokingIndustryMember" xlink:href="aon-20211231.xsd#aon_AviationandAerospaceBrokingIndustryMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AviationandAerospaceBrokingIndustryMember" xlink:to="lab_aon_AviationandAerospaceBrokingIndustryMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock_14186ff2-2c30-4920-bf3b-a6689ab0ba76_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Current Assets </link:label>
<link:label id="lab_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Current Assets [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfOtherCurrentAssetsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive_ab32a7b0-2e05-4121-9603-7279d2736c16_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Thereafter </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due After Year Five </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due After Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueAfterYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShortTermDebtTypeDomain_37db6f03-e8ba-4061-8f4c-b6ef3fd6971e_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Type [Domain] </link:label>
<link:label id="lab_us-gaap_ShortTermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt, Type [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain" xlink:to="lab_us-gaap_ShortTermDebtTypeDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodTax_8e208c09-55e7-4712-ac3b-5954c2361882_terseLabel_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tax expense </link:label>
<link:label id="lab_us-gaap_ReclassificationFromAociCurrentPeriodTax_label_en-US" xlink:label="lab_us-gaap_ReclassificationFromAociCurrentPeriodTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reclassification from AOCI, Current Period, Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax" xlink:to="lab_us-gaap_ReclassificationFromAociCurrentPeriodTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TreasuryStockValueAcquiredCostMethod_d4eea334-c381-4b53-bfa9-abe780b0fbcf_terseLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total repurchase cost </link:label>
<link:label id="lab_us-gaap_TreasuryStockValueAcquiredCostMethod_label_en-US" xlink:label="lab_us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Value, Acquired, Cost Method </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:to="lab_us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TreasuryStockAcquiredAverageCostPerShare_efadd69d-9554-406d-a107-b773a8171e45_terseLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Average price per share (in dollars per share) </link:label>
<link:label id="lab_us-gaap_TreasuryStockAcquiredAverageCostPerShare_label_en-US" xlink:label="lab_us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock Acquired, Average Cost Per Share </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:to="lab_us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ForeignPlanMember_0d263ed7-40db-4594-8553-f861523c838c_verboseLabel_en-US" xlink:label="lab_us-gaap_ForeignPlanMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Plan </link:label>
<link:label id="lab_us-gaap_ForeignPlanMember_label_en-US" xlink:label="lab_us-gaap_ForeignPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Plan [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignPlanMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignPlanMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignPlanMember" xlink:to="lab_us-gaap_ForeignPlanMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_fbe33c70-9be1-4768-b583-e80e09ffe4a9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2023 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_6755febf-276f-4b8a-bb83-587a7dc78232_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected future benefit payments 2023 </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, Year Two </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:type="arc" order="1"/>
<link:label id="lab_srt_MinimumMember_3b9565be-daf4-480e-ba99-09c15e61b0dc_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Minimum </link:label>
<link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Minimum [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MinimumMember" xlink:to="lab_srt_MinimumMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo_1ad97031-381c-4b97-bbd5-eccc75f3266f_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2023 </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Two </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Two </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_a4b083b3-99a7-412c-8ed5-a164a5233b6f_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other assets and liabilities </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Other Operating Assets and Liabilities, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_fe25b4e2-4816-45c6-8a64-812b6d725dfd_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2023 </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, Year Two </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCredit_115ee3e2-076a-4db5-ab83-3bda43d57ce2_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of credit outstanding </link:label>
<link:label id="lab_us-gaap_LineOfCredit_label_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Line of Credit </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCredit" xlink:to="lab_us-gaap_LineOfCredit" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_30c09ee8-701b-4fc2-a27a-c35335c70466_terseLabel_en-US" xlink:label="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effect of exchange rates on cash and cash equivalents and funds held on behalf of clients </link:label>
<link:label id="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_label_en-US" xlink:label="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_1a3c2009-8e48-48b0-8241-387080e35d5f_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Revenues from External Customers and Long-Lived Assets [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Revenues from External Customers and Long-Lived Assets [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_73248183-ec9e-4f83-aea8-a7d3c8d339ad_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income before income taxes </link:label>
<link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CoverWalletIncMember_7ac77719-23e3-462c-83f2-2cc697db6e62_terseLabel_en-US" xlink:label="lab_aon_CoverWalletIncMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cover Wallet Inc. </link:label>
<link:label id="lab_aon_CoverWalletIncMember_label_en-US" xlink:label="lab_aon_CoverWalletIncMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cover Wallet Inc. [Member] </link:label>
<link:label id="lab_aon_CoverWalletIncMember_documentation_en-US" xlink:label="lab_aon_CoverWalletIncMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cover Wallet Inc. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CoverWalletIncMember" xlink:href="aon-20211231.xsd#aon_CoverWalletIncMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CoverWalletIncMember" xlink:to="lab_aon_CoverWalletIncMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_SeniorNotes4.25PercentDue2042Member_509299d3-4f5b-4949-a815-e41184cb93b6_terseLabel_en-US" xlink:label="lab_aon_SeniorNotes4.25PercentDue2042Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.25% Senior Notes due December 2042 </link:label>
<link:label id="lab_aon_SeniorNotes4.25PercentDue2042Member_label_en-US" xlink:label="lab_aon_SeniorNotes4.25PercentDue2042Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Senior Notes 4.25 Percent Due 2042 [Member] </link:label>
<link:label id="lab_aon_SeniorNotes4.25PercentDue2042Member_documentation_en-US" xlink:label="lab_aon_SeniorNotes4.25PercentDue2042Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the senior notes that bear an interest rate of 4.25 percent and will mature in 2042. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_SeniorNotes4.25PercentDue2042Member" xlink:href="aon-20211231.xsd#aon_SeniorNotes4.25PercentDue2042Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_SeniorNotes4.25PercentDue2042Member" xlink:to="lab_aon_SeniorNotes4.25PercentDue2042Member" xlink:type="arc" order="1"/>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAxis_000cd2a9-08bb-45f3-b341-f50881e9f111_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption [Axis] </link:label>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAxis_label_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:to="lab_srt_CumulativeEffectPeriodOfAdoptionAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent_3423bc22-ccd4-4e49-99ba-eee0901e7453_terseLabel_en-US" xlink:label="lab_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Transition tax for accumulated foreign earnings, noncurrent </link:label>
<link:label id="lab_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent_label_en-US" xlink:label="lab_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent" xlink:to="lab_us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_271d9784-3bcf-4513-919c-948a3df8e8a7_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Percentage of capital acquired </link:label>
<link:label id="lab_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition, Percentage of Voting Interests Acquired </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:to="lab_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_478e94ce-e01a-4390-820b-185554d746a7_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2025 </link:label>
<link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Term Debt, Maturity, Year Four </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DistributableReservesAvailableAmount_77836595-0313-49c5-9ed3-42effb070714_terseLabel_en-US" xlink:label="lab_aon_DistributableReservesAvailableAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Distributable reserves available amount </link:label>
<link:label id="lab_aon_DistributableReservesAvailableAmount_label_en-US" xlink:label="lab_aon_DistributableReservesAvailableAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Distributable Reserves Available, Amount </link:label>
<link:label id="lab_aon_DistributableReservesAvailableAmount_documentation_en-US" xlink:label="lab_aon_DistributableReservesAvailableAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the amount of distributable reserves maintained by the entity. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DistributableReservesAvailableAmount" xlink:href="aon-20211231.xsd#aon_DistributableReservesAvailableAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DistributableReservesAvailableAmount" xlink:to="lab_aon_DistributableReservesAvailableAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear_2a968097-2e9d-4c06-8b83-dd49f8954a84_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected amortization of prior service credit, next fiscal year </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_4aef90df-5575-4876-b71a-1ba23100f935_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Acquisition of businesses, net of cash and funds held on behalf of clients </link:label>
<link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to Acquire Businesses, Net of Cash Acquired </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedTranslationAdjustmentMember_1ab928ca-6a4d-4749-a978-a8d06a0f2015_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Currency Translation Adjustments </link:label>
<link:label id="lab_us-gaap_AccumulatedTranslationAdjustmentMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Foreign Currency Adjustment Attributable to Parent [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:to="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtDisclosureTextBlock_907007bc-4c48-4c71-a497-375c1e011f87_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt </link:label>
<link:label id="lab_us-gaap_DebtDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Disclosure [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureTextBlock" xlink:to="lab_us-gaap_DebtDisclosureTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_02f0b63a-0824-4667-b95e-a56aaf3a6eb8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income From Continuing Operations Before Income Tax </link:label>
<link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCreditMember_3209c194-1c7c-48ef-bfae-ed5f0bf3a2d7_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit </link:label>
<link:label id="lab_us-gaap_LineOfCreditMember_label_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditMember" xlink:to="lab_us-gaap_LineOfCreditMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_9797e20a-0430-453b-80fe-50015f94c064_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-Based Compensation Plans </link:label>
<link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:to="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SeniorNotesMember_b329250a-b680-46a8-bb3f-4daff3cc3cad_terseLabel_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Senior Notes </link:label>
<link:label id="lab_us-gaap_SeniorNotesMember_label_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Senior Notes [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeniorNotesMember" xlink:to="lab_us-gaap_SeniorNotesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueInputsLevel3Member_9f160ec7-63c1-4c00-88ec-4b3b5168521e_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Significant Unobservable Inputs (Level 3) </link:label>
<link:label id="lab_us-gaap_FairValueInputsLevel3Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Inputs, Level 3 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel3Member" xlink:to="lab_us-gaap_FairValueInputsLevel3Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_8c3b0352-da44-4f44-b31e-46c5189e650e_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash dividends to shareholders </link:label>
<link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments of Ordinary Dividends, Common Stock </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:to="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CapitalizedContractCostDomain_bbc234a4-6f31-40ef-85e6-a47b62e0296a_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost [Domain] </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostDomain_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalizedContractCostDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostDomain" xlink:to="lab_us-gaap_CapitalizedContractCostDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock_0959b7cb-6e87-414d-9545-ad9dc4b1688d_terseLabel_en-US" xlink:label="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Performance-based Plans Information </link:label>
<link:label id="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock_label_en-US" xlink:label="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Performance Based Plans [Table Text Block] </link:label>
<link:label id="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock_documentation_en-US" xlink:label="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> This text block may be used to capture information pertaining to performance based plans. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:href="aon-20211231.xsd#aon_ScheduleofPerformanceBasedPlansTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:to="lab_aon_ScheduleofPerformanceBasedPlansTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NumberOfReportableSegments_804f40dc-2276-43c3-ba18-2a834c57e86e_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of reportable segments </link:label>
<link:label id="lab_us-gaap_NumberOfReportableSegments_label_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of Reportable Segments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfReportableSegments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfReportableSegments" xlink:to="lab_us-gaap_NumberOfReportableSegments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_20a7c48a-2adc-4715-af49-6a0ab378ddb7_terseLabel_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Letters of credit outstanding </link:label>
<link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_label_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Letters of Credit Outstanding, Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:to="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_8c80ef18-36a0-45f3-bb5b-230680ce1916_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency remeasurement </link:label>
<link:label id="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign Currency Transaction Gain (Loss), before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:to="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PensionExpense_35408856-7cab-4353-abc3-5fabdf900827_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PensionExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension and other postretirement </link:label>
<link:label id="lab_us-gaap_PensionExpense_label_en-US" xlink:label="lab_us-gaap_PensionExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension Cost (Reversal of Cost) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionExpense" xlink:to="lab_us-gaap_PensionExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FundsHeldForClients_efff9926-5874-4b56-b6f3-98eb6a100ee7_terseLabel_en-US" xlink:label="lab_us-gaap_FundsHeldForClients" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Funds held on behalf of clients </link:label>
<link:label id="lab_us-gaap_FundsHeldForClients_label_en-US" xlink:label="lab_us-gaap_FundsHeldForClients" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Funds Held for Clients </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FundsHeldForClients" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FundsHeldForClients"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FundsHeldForClients" xlink:to="lab_us-gaap_FundsHeldForClients" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NonoperatingIncomeExpense_579479a0-d114-406d-b9d5-79e84d335fd5_totalLabel_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_NonoperatingIncomeExpense_label_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Nonoperating Income (Expense) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="lab_us-gaap_NonoperatingIncomeExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_f2d78b3c-9086-42f6-8a9e-68c8c4e6a803_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue [Line Items] </link:label>
<link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:to="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GoodwillAcquiredDuringPeriod_f3de5d8f-748e-44d7-b226-310357ae7ba1_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill related to current year acquisitions </link:label>
<link:label id="lab_us-gaap_GoodwillAcquiredDuringPeriod_label_en-US" xlink:label="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill, Acquired During Period </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAcquiredDuringPeriod" xlink:to="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_a42ca5a2-2a30-42f0-951a-5cb761f4dc1b_terseLabel_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Basis of Accounting </link:label>
<link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Basis of Accounting, Policy [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:to="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PerformanceSharesMember_f9a36773-b28b-4b23-b64e-91ae94f9f796_verboseLabel_en-US" xlink:label="lab_us-gaap_PerformanceSharesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Performance share awards </link:label>
<link:label id="lab_us-gaap_PerformanceSharesMember_a5c72979-ae47-4e73-882a-4424bd76314d_terseLabel_en-US" xlink:label="lab_us-gaap_PerformanceSharesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Performance-based Awards </link:label>
<link:label id="lab_us-gaap_PerformanceSharesMember_label_en-US" xlink:label="lab_us-gaap_PerformanceSharesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Performance Shares [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PerformanceSharesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PerformanceSharesMember" xlink:to="lab_us-gaap_PerformanceSharesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_19374179-2f20-402e-9148-b3c0d32fe7dd_terseLabel_en-US" xlink:label="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Post-Retirement Benefits </link:label>
<link:label id="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_label_en-US" xlink:label="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Postretirement Benefits Plan [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:to="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_d3dd7691-fefe-4221-8c72-d0bfe8bf7847_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated other comprehensive loss </link:label>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Income (Loss), Net of Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityEmergingGrowthCompany_5318b2b7-a95e-4800-a332-f1dd15f80da1_terseLabel_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Emerging Growth Company </link:label>
<link:label id="lab_dei_EntityEmergingGrowthCompany_label_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Emerging Growth Company </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityEmergingGrowthCompany"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityEmergingGrowthCompany" xlink:to="lab_dei_EntityEmergingGrowthCompany" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_8a690506-8056-40ef-9944-246e9d7d0dc7_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Allowance for doubtful accounts </link:label>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_b85180cb-7a6a-4e8a-8853-cbd14f916f62_periodStartLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at beginning of period </link:label>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_79b5a856-a561-4b34-bec5-589674b6c95e_periodEndLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at end of period </link:label>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance for Credit Loss, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccruedIncomeTaxesNoncurrent_c53b002b-bda9-416f-8a05-baaa8796f7f9_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedIncomeTaxesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Taxes payable </link:label>
<link:label id="lab_us-gaap_AccruedIncomeTaxesNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccruedIncomeTaxesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accrued Income Taxes, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedIncomeTaxesNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedIncomeTaxesNoncurrent" xlink:to="lab_us-gaap_AccruedIncomeTaxesNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_189c9cdb-f5f5-4f71-98b6-418e8650627e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency impact </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_aon_InterestCarryforward_16be5532-b43a-45ff-8367-4a704221e4e7_terseLabel_en-US" xlink:label="lab_aon_InterestCarryforward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest carryforwards </link:label>
<link:label id="lab_aon_InterestCarryforward_label_en-US" xlink:label="lab_aon_InterestCarryforward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest Carryforward </link:label>
<link:label id="lab_aon_InterestCarryforward_documentation_en-US" xlink:label="lab_aon_InterestCarryforward" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest Carryforward </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_InterestCarryforward" xlink:href="aon-20211231.xsd#aon_InterestCarryforward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_InterestCarryforward" xlink:to="lab_aon_InterestCarryforward" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisposalGroupClassificationAxis_695d2d32-3a45-4787-8cd0-decf2df8b893_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Classification [Axis] </link:label>
<link:label id="lab_us-gaap_DisposalGroupClassificationAxis_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disposal Group Classification [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis" xlink:to="lab_us-gaap_DisposalGroupClassificationAxis" xlink:type="arc" order="1"/>
<link:label id="lab_dei_AuditorName_85103c5c-ecc8-4452-80a3-6f120c3491f3_terseLabel_en-US" xlink:label="lab_dei_AuditorName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Name </link:label>
<link:label id="lab_dei_AuditorName_label_en-US" xlink:label="lab_dei_AuditorName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Name </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_AuditorName" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorName"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorName" xlink:to="lab_dei_AuditorName" xlink:type="arc" order="1"/>
<link:label id="lab_dei_CoverAbstract_c3e4a229-065e-4d10-84d7-716f0c8fe03d_terseLabel_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cover [Abstract] </link:label>
<link:label id="lab_dei_CoverAbstract_label_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cover [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CoverAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SecuredDebtCurrent_b2540af3-62b2-4bf9-8914-ca5ab5108515_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebtCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current portion of long-term debt </link:label>
<link:label id="lab_us-gaap_SecuredDebtCurrent_label_en-US" xlink:label="lab_us-gaap_SecuredDebtCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Secured Debt, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SecuredDebtCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredDebtCurrent" xlink:to="lab_us-gaap_SecuredDebtCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_9ecb050b-0398-4378-963a-f0c956abeef2_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenues from External Customers and Long-Lived Assets [Line Items] </link:label>
<link:label id="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_label_en-US" xlink:label="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Revenues from External Customers and Long-Lived Assets [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CostsAndExpenses_70fd0ea2-9563-4f62-a2fd-9095047a5b52_totalLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total operating expenses </link:label>
<link:label id="lab_us-gaap_CostsAndExpenses_label_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Costs and Expenses </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostsAndExpenses"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostsAndExpenses" xlink:to="lab_us-gaap_CostsAndExpenses" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_38083698-424a-475b-a25f-fe9ac6a22057_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Current, Statement of Financial Position [Extensible List] </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:to="lab_us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:type="arc" order="1"/>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_f10a3c0d-8f03-497f-900a-3735699f2f3d_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption, Adjusted Balance </link:label>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_label_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption, Adjusted Balance [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember" xlink:to="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_BusinessCombinationTerminationFees_37c339dc-ab07-419a-bc60-37fe2ac66f4c_terseLabel_en-US" xlink:label="lab_aon_BusinessCombinationTerminationFees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Termination fee </link:label>
<link:label id="lab_aon_BusinessCombinationTerminationFees_label_en-US" xlink:label="lab_aon_BusinessCombinationTerminationFees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Termination Fees </link:label>
<link:label id="lab_aon_BusinessCombinationTerminationFees_documentation_en-US" xlink:label="lab_aon_BusinessCombinationTerminationFees" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Termination Fees </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_BusinessCombinationTerminationFees" xlink:href="aon-20211231.xsd#aon_BusinessCombinationTerminationFees"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_BusinessCombinationTerminationFees" xlink:to="lab_aon_BusinessCombinationTerminationFees" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtLongtermAndShorttermCombinedAmount_76b708fa-b576-471f-a737-621bb0474122_totalLabel_en-US" xlink:label="lab_us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total debt </link:label>
<link:label id="lab_us-gaap_DebtLongtermAndShorttermCombinedAmount_label_en-US" xlink:label="lab_us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt, Long-term and Short-term, Combined Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:to="lab_us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherCurrentLiabilitiesTableTextBlock_c18589ff-cee5-4874-9749-b5ad06d36dad_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Current Liabilities </link:label>
<link:label id="lab_us-gaap_OtherCurrentLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Current Liabilities [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentLiabilitiesTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:to="lab_us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_fa37f031-6980-498b-a849-ad4c26f2d9aa_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Imputed interest </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, Undiscounted Excess Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_17ac1ca2-c25a-4c0a-ab50-d089e3710c07_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Rate of compensation increase </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FiduciaryAssets_cae910b1-b07e-4448-a521-c00a62ed44fc_terseLabel_en-US" xlink:label="lab_aon_FiduciaryAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary assets </link:label>
<link:label id="lab_aon_FiduciaryAssets_label_en-US" xlink:label="lab_aon_FiduciaryAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Assets. </link:label>
<link:label id="lab_aon_FiduciaryAssets_documentation_en-US" xlink:label="lab_aon_FiduciaryAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts due from clients and insurance companies, along with short-term investments held by the entity that will be paid to clients and insurance companies, net of a reserve for doubtful accounts. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FiduciaryAssets" xlink:href="aon-20211231.xsd#aon_FiduciaryAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FiduciaryAssets" xlink:to="lab_aon_FiduciaryAssets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_c0dcb26f-045c-409d-be61-1e357eb5f209_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts Recognized in Accumulated Other Comprehensive Loss that have not yet been Recognized as Components of net Periodic Benefit Cost </link:label>
<link:label id="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinancialInstrumentAxis_5916d53a-8ff6-4a0c-9dd4-242e2df7c47d_terseLabel_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial Instrument [Axis] </link:label>
<link:label id="lab_us-gaap_FinancialInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial Instrument [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentAxis" xlink:to="lab_us-gaap_FinancialInstrumentAxis" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent_33d713b9-6dc2-4990-80b6-fd577c06b043_terseLabel_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-deductible transaction costs </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent_label_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Transaction Costs, Percent </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent_documentation_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Transaction Costs, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:href="aon-20211231.xsd#aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:to="lab_aon_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseTransactionCostsPercent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_75dd5bdc-b9ea-4f5b-9fe3-5789efc45016_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Imputed interest </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, Undiscounted Excess Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_abbaa3e0-b5c9-4ea8-92dd-b7a5658a8993_terseLabel_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current: </link:label>
<link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current Income Tax Expense (Benefit), Continuing Operations [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1_dc8432bd-33af-4351-94cd-413fafd2dbf0_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity interest in acquiree </link:label>
<link:label id="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1" xlink:to="lab_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member_7c83d816-58a2-43ff-ab6e-959ec4af6243_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.60% Senior Notes due 2031 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plc’s 2.60% Senior Notes Due 2031 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plc’s 2.60% Senior Notes Due 2031 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:to="lab_aon_GuaranteesOfAonPlcs260SeniorNotesDue2031Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_66fed417-e991-4e99-8eb5-f7e126aa80a8_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, to be Paid, Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingIncomeLoss_4886ac78-d0db-4a9f-813f-4de498bebb0e_totalLabel_en-US" xlink:label="lab_us-gaap_OperatingIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating income </link:label>
<link:label id="lab_us-gaap_OperatingIncomeLoss_label_en-US" xlink:label="lab_us-gaap_OperatingIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Income (Loss) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="lab_us-gaap_OperatingIncomeLoss" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract_4044dbbe-3e2f-4e86-8dc5-b11727ecc068_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Actual return on plan assets: </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract" xlink:to="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_68003e70-5f8f-44f4-a48c-5e518739c1a2_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrent_0eb76e9a-3c07-49c4-9258-8a9cb593ede8_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Liability, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_9c5f991d-3466-41ef-920e-bc1fd7e82143_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Less: Other comprehensive income (loss) attributable to noncontrolling interests </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_c52eb7b4-60e5-4f78-925d-ac88fe38f6ca_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2023 </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Expected Amortization, Year Two </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_HedgingDesignationAxis_5309b4ec-8cb0-49f2-a98a-680181d46df8_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingDesignationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Designation [Axis] </link:label>
<link:label id="lab_us-gaap_HedgingDesignationAxis_label_en-US" xlink:label="lab_us-gaap_HedgingDesignationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Hedging Designation [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingDesignationAxis" xlink:to="lab_us-gaap_HedgingDesignationAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensation_44b874bc-d26a-4c0b-8d1d-bdf5850c9c9d_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based compensation expense </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Noncash Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensation" xlink:to="lab_us-gaap_ShareBasedCompensation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_7b7e1a6d-490d-45ae-8c0b-6cbb16e7443d_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents </link:label>
<link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and Cash Equivalents, at Carrying Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_Depreciation_4b8976d8-8bbc-44ea-a2d5-7ecfefeafc4d_terseLabel_en-US" xlink:label="lab_us-gaap_Depreciation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Depreciation of fixed assets </link:label>
<link:label id="lab_us-gaap_Depreciation_label_en-US" xlink:label="lab_us-gaap_Depreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Depreciation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Depreciation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Depreciation" xlink:to="lab_us-gaap_Depreciation" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member_60d30794-e7f9-4914-8b7d-a063d23c1cc2_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.90% Senior Notes due 2051 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.90 Senior Notes Due 2051 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 2.90 Senior Notes Due 2051 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:to="lab_aon_GuaranteesOfAonPlcs290SeniorNotesDue2051Member" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member_ca07d364-f79f-4163-841a-4aa930d73940_terseLabel_en-US" xlink:label="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 8.205% Junior Subordinated Notes due January 2027 </link:label>
<link:label id="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member_label_en-US" xlink:label="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 8.205% Junior Subordinated Notes Due January 2027 [Member] </link:label>
<link:label id="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member_documentation_en-US" xlink:label="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> This element represents the junior subordinated deferrable interest debentures that bear an interest rate of 8.205 percent and will mature in 2027. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:href="aon-20211231.xsd#aon_A8205JuniorSubordinatedNotesDueJanuary2027Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:to="lab_aon_A8205JuniorSubordinatedNotesDueJanuary2027Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanRealEstateMember_6250c84e-1dbf-4e39-8be3-144918d8f6cf_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Real estate </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanRealEstateMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Real Estate [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanRealEstateMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:to="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_d0aba9b6-fb17-432f-9884-f63a5b38345a_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] </link:label>
<link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:to="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeNotionalAmount_fdd096e2-c8a8-4134-bc18-26ff466aa881_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeNotionalAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative, Notional Amount </link:label>
<link:label id="lab_us-gaap_DerivativeNotionalAmount_label_en-US" xlink:label="lab_us-gaap_DerivativeNotionalAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative, Notional Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeNotionalAmount" xlink:to="lab_us-gaap_DerivativeNotionalAmount" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FiduciaryLiabilities_800ca3bd-6d55-4f7e-add3-24c640903f67_terseLabel_en-US" xlink:label="lab_aon_FiduciaryLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary liabilities </link:label>
<link:label id="lab_aon_FiduciaryLiabilities_label_en-US" xlink:label="lab_aon_FiduciaryLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fiduciary Liabilities </link:label>
<link:label id="lab_aon_FiduciaryLiabilities_documentation_en-US" xlink:label="lab_aon_FiduciaryLiabilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Carrying value as of the balance sheet date of Insurance premiums payable and claims payable. Insurance premiums payable represent premiums collected from insured's and, after deducting the reporting entity's commissions, are due to the respective insurers. Claims payable represent claim payments received from the respective insurers and due to the insured. These unremitted insurance premiums and claims are held in a fiduciary capacity. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FiduciaryLiabilities" xlink:href="aon-20211231.xsd#aon_FiduciaryLiabilities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FiduciaryLiabilities" xlink:to="lab_aon_FiduciaryLiabilities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_59fd871b-d7e7-4c90-852b-16ac9fc90141_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Benefit payments </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation, Benefits Paid </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_e75c74d3-09f7-4a8b-ad01-542b0d158236_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency impact </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_fd13af17-5214-4c5e-93db-382fdb03a5ed_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign exchange </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NoncashLeaseActivitiesAbstract_ba54da42-f16f-4549-81ab-831072675776_terseLabel_en-US" xlink:label="lab_aon_NoncashLeaseActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-cash related activities </link:label>
<link:label id="lab_aon_NoncashLeaseActivitiesAbstract_label_en-US" xlink:label="lab_aon_NoncashLeaseActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-cash Lease Activities [Abstract] </link:label>
<link:label id="lab_aon_NoncashLeaseActivitiesAbstract_documentation_en-US" xlink:label="lab_aon_NoncashLeaseActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-cash Lease Activities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NoncashLeaseActivitiesAbstract" xlink:href="aon-20211231.xsd#aon_NoncashLeaseActivitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NoncashLeaseActivitiesAbstract" xlink:to="lab_aon_NoncashLeaseActivitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_5ebf4c25-3219-4553-95ee-05a1a128eae3_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capital expenditures </link:label>
<link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to Acquire Property, Plant, and Equipment </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherLiabilitiesCurrent_e1b7de08-906a-4561-b1e1-9df42293db56_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other current liabilities </link:label>
<link:label id="lab_us-gaap_OtherLiabilitiesCurrent_9f207093-d7e1-4a31-9cba-d9050f525cb3_totalLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_OtherLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Liabilities, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherLiabilitiesCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_ffec40d8-d766-4593-a11a-1819924fb1d8_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employer contributions </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Contributions by Employer </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:to="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_cd7934b5-b060-4722-93d1-008453c43091_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated benefit obligation at end of year </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_0aff8bb7-2909-4e41-b4bd-b2134aaf574e_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated projected benefit obligation </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Accumulated Benefit Obligation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_Liabilities_459c2bc3-da21-4917-aaf8-1a5b6d1c77c2_totalLabel_en-US" xlink:label="lab_us-gaap_Liabilities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total liabilities </link:label>
<link:label id="lab_us-gaap_Liabilities_label_en-US" xlink:label="lab_us-gaap_Liabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Liabilities" xlink:to="lab_us-gaap_Liabilities" xlink:type="arc" order="1"/>
<link:label id="lab_aon_USCommercialPaperProgramMember_8432d82f-9392-40af-a09a-13ff49591993_terseLabel_en-US" xlink:label="lab_aon_USCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U. S. Program </link:label>
<link:label id="lab_aon_USCommercialPaperProgramMember_label_en-US" xlink:label="lab_aon_USCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U. S. Commercial Paper Program [Member] </link:label>
<link:label id="lab_aon_USCommercialPaperProgramMember_documentation_en-US" xlink:label="lab_aon_USCommercialPaperProgramMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U. S. Commercial Paper Program </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_USCommercialPaperProgramMember" xlink:href="aon-20211231.xsd#aon_USCommercialPaperProgramMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_USCommercialPaperProgramMember" xlink:to="lab_aon_USCommercialPaperProgramMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_1210f7a5-9a99-4ae3-8335-3b128766794f_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Expected Amortization, Year One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:type="arc" order="1"/>
<link:label id="lab_srt_ConsolidationItemsAxis_79831763-c09c-4ffd-8c3a-639c804be030_terseLabel_en-US" xlink:label="lab_srt_ConsolidationItemsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consolidation Items [Axis] </link:label>
<link:label id="lab_srt_ConsolidationItemsAxis_label_en-US" xlink:label="lab_srt_ConsolidationItemsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Consolidation Items [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidationItemsAxis" xlink:to="lab_srt_ConsolidationItemsAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OperatingLossCarryforwards_8dc3ce8e-9f5b-4695-9c06-032bf5e7adde_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating loss carryforwards </link:label>
<link:label id="lab_us-gaap_OperatingLossCarryforwards_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Loss Carryforwards </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwards" xlink:to="lab_us-gaap_OperatingLossCarryforwards" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockSharesIssued_bcaa22cd-f7a6-4b12-83d8-5c39eaeda426_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ordinary shares, issued shares (in Shares) </link:label>
<link:label id="lab_us-gaap_CommonStockSharesIssued_098eb1c6-4835-4780-aa88-ccb11962cd3c_periodStartLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Beginning Balance (in shares) </link:label>
<link:label id="lab_us-gaap_CommonStockSharesIssued_862feb62-a75c-4830-8db6-cc9eea518eb4_periodEndLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ending Balance (in shares) </link:label>
<link:label id="lab_us-gaap_CommonStockSharesIssued_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock, Shares, Issued </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesIssued" xlink:to="lab_us-gaap_CommonStockSharesIssued" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock_2eb1ac9c-9521-4a15-bc36-f175b82fa20a_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Values of Pension Plan Assets </link:label>
<link:label id="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Changes in Fair Value of Plan Assets [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_ccf4ca19-ab26-4056-b360-d73860b8aa33_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated other comprehensive loss </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_906569d8-a4f1-44e6-affa-a4c1dd10a666_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net amount recognized </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_b61d7670-2ef6-455d-a3a6-f9e9e635bd6d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted-Average Assumptions Used to Determine Future Benefit Obligations and Net Periodic Benefit Cost </link:label>
<link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAssumptionsUsedTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityAddressCityOrTown_8a9b0523-9a16-4414-9742-49ec020dd798_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, City or Town </link:label>
<link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Address, City or Town </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCityOrTown"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressCityOrTown" xlink:to="lab_dei_EntityAddressCityOrTown" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NEBCMember_096449b5-ff69-4d14-86aa-6b35fa5973a4_terseLabel_en-US" xlink:label="lab_aon_NEBCMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> N E B C </link:label>
<link:label id="lab_aon_NEBCMember_label_en-US" xlink:label="lab_aon_NEBCMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> N E B C [Member] </link:label>
<link:label id="lab_aon_NEBCMember_documentation_en-US" xlink:label="lab_aon_NEBCMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> N E B C </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NEBCMember" xlink:href="aon-20211231.xsd#aon_NEBCMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NEBCMember" xlink:to="lab_aon_NEBCMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_c376b401-0e7d-4f61-9173-37fc2e30a154_terseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Extinguishment of debt </link:label>
<link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_d460b908-738a-4f1f-a8a8-262b226a1009_negatedLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss on extinguishment of debt </link:label>
<link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_label_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (Loss) on Extinguishment of Debt </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:to="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AssimediaSAMember_0c34a7da-8da4-4ea3-b04a-38722b5e163c_terseLabel_en-US" xlink:label="lab_aon_AssimediaSAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assimedia SA </link:label>
<link:label id="lab_aon_AssimediaSAMember_label_en-US" xlink:label="lab_aon_AssimediaSAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assimedia SA [Member] </link:label>
<link:label id="lab_aon_AssimediaSAMember_documentation_en-US" xlink:label="lab_aon_AssimediaSAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assimedia SA </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AssimediaSAMember" xlink:href="aon-20211231.xsd#aon_AssimediaSAMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AssimediaSAMember" xlink:to="lab_aon_AssimediaSAMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_e39ab1dc-34b1-49f4-a0be-df41334e35e5_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Estimated Future Benefit Payments </link:label>
<link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Expected Benefit Payments [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_4b2674e5-4262-4d00-a612-2f956522ec10_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Accumulated Other Comprehensive Loss, Net of Related Tax </link:label>
<link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CreditFacilityExpiringSeptember2026Member_2db769cc-c88d-4313-9f44-3cc8dec82aef_terseLabel_en-US" xlink:label="lab_aon_CreditFacilityExpiringSeptember2026Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring September 2026 </link:label>
<link:label id="lab_aon_CreditFacilityExpiringSeptember2026Member_label_en-US" xlink:label="lab_aon_CreditFacilityExpiringSeptember2026Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring September 2026 [Member] </link:label>
<link:label id="lab_aon_CreditFacilityExpiringSeptember2026Member_documentation_en-US" xlink:label="lab_aon_CreditFacilityExpiringSeptember2026Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring September 2026 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CreditFacilityExpiringSeptember2026Member" xlink:href="aon-20211231.xsd#aon_CreditFacilityExpiringSeptember2026Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CreditFacilityExpiringSeptember2026Member" xlink:to="lab_aon_CreditFacilityExpiringSeptember2026Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RetirementPlanTypeAxis_6f48b52c-442c-4e0e-b61b-6e33479cf994_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Type [Axis] </link:label>
<link:label id="lab_us-gaap_RetirementPlanTypeAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Type [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanTypeAxis" xlink:to="lab_us-gaap_RetirementPlanTypeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BalanceSheetLocationAxis_ea3d7e9a-35dd-4e9d-bedf-594cc2d1ff9f_terseLabel_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance Sheet Location [Axis] </link:label>
<link:label id="lab_us-gaap_BalanceSheetLocationAxis_label_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance Sheet Location [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BalanceSheetLocationAxis" xlink:to="lab_us-gaap_BalanceSheetLocationAxis" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent_59e5709b-b0c1-4ad3-8b82-194209239f25_terseLabel_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> PSA, actual shares issued, percent </link:label>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent_label_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued, Percent </link:label>
<link:label id="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent_documentation_en-US" xlink:label="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:href="aon-20211231.xsd#aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:to="lab_aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_414529c2-1c3a-47ca-b79a-2b0133717e4b_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Measurement Frequency [Domain] </link:label>
<link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Measurement Frequency [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_InterestExpense_76e9a1ae-74dc-4504-9d69-a2eac90400a5_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest expense </link:label>
<link:label id="lab_us-gaap_InterestExpense_label_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpense" xlink:to="lab_us-gaap_InterestExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_1ed56c92-a44f-4656-a325-6b950f2aa728_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Liability, to be Paid, Year One </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_f1dcdcc1-2e51-4859-b067-9a45380d7264_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected return on plan assets, net of administration expenses </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition_0c14a38c-0a4f-49c9-b31e-103d42fdd2ea_terseLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business combinations </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Increase Resulting from Acquisition </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition" xlink:to="lab_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_813716df-7c68-4acd-8397-cacd7f684001_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax expense (benefit): </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] </link:label>
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<link:label id="lab_us-gaap_CapitalizedContractCostAmortization_0ae51ed5-5837-4e5b-aabb-420a62c7bdad_negatedLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amortization </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostAmortization_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost, Amortization </link:label>
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<link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_59c8c1f2-7e80-4d63-9fbc-b66e7ace98c0_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2022 </link:label>
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<link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_12981c0d-4f5b-48dd-b17b-76fe105f9187_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retained earnings (accumulated deficit) </link:label>
<link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retained Earnings (Accumulated Deficit) </link:label>
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<link:label id="lab_srt_LitigationCaseTypeDomain_6898a983-ef81-402b-a580-15e033da8614_terseLabel_en-US" xlink:label="lab_srt_LitigationCaseTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Case [Domain] </link:label>
<link:label id="lab_srt_LitigationCaseTypeDomain_label_en-US" xlink:label="lab_srt_LitigationCaseTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Case [Domain] </link:label>
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<link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_a33a70ca-1cc0-471e-ba97-8cca19baf9f9_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Stockholders' Equity [Abstract] </link:label>
<link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Stockholders' Equity [Abstract] </link:label>
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<link:label id="lab_aon_A280SeniorNotesDueMarch2021Member_f98ef6fd-5ee1-4374-9f9b-22aa81d5debf_terseLabel_en-US" xlink:label="lab_aon_A280SeniorNotesDueMarch2021Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes due March 2021 </link:label>
<link:label id="lab_aon_A280SeniorNotesDueMarch2021Member_label_en-US" xlink:label="lab_aon_A280SeniorNotesDueMarch2021Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes Due March 2021 [Member] </link:label>
<link:label id="lab_aon_A280SeniorNotesDueMarch2021Member_documentation_en-US" xlink:label="lab_aon_A280SeniorNotesDueMarch2021Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.80% Senior Notes Due March 2021 </link:label>
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<link:label id="lab_dei_EntityFilerCategory_c0618de0-a40d-462c-98ea-73902bf9253e_terseLabel_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Filer Category </link:label>
<link:label id="lab_dei_EntityFilerCategory_label_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Filer Category </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFilerCategory"/>
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<link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_9395f417-b31c-47e6-bb4a-5eb6b4d9090e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Gains (Losses) </link:label>
<link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Instruments, Gain (Loss) [Table Text Block] </link:label>
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<link:label id="lab_us-gaap_PropertyLeaseGuaranteeMember_4381ce9c-40bd-44ee-ae58-4cce17312aea_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyLeaseGuaranteeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property Lease Guarantee </link:label>
<link:label id="lab_us-gaap_PropertyLeaseGuaranteeMember_label_en-US" xlink:label="lab_us-gaap_PropertyLeaseGuaranteeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property Lease Guarantee [Member] </link:label>
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<link:label id="lab_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome_d908b842-7c1c-4ff5-82e8-17b6cdfdc1ba_negatedLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred costs </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Tax Deferred Income </link:label>
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<link:label id="lab_us-gaap_OtherNoncurrentAssetsMember_209ba23f-a8fc-4cdb-9f14-4b9c2e227f35_terseLabel_en-US" xlink:label="lab_us-gaap_OtherNoncurrentAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Noncurrent Assets </link:label>
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<link:label id="lab_us-gaap_ShortTermInvestments_4d8ba6a1-14dc-4e0b-a49b-112e4c968c9b_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term investments </link:label>
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<link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_52a182a6-6035-4375-bd4d-0150189c6e10_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2023 </link:label>
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<link:label id="lab_us-gaap_DerivativeTermOfContract_7b2734ca-3ffe-4f3d-9112-f517943d5b2f_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeTermOfContract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative term of contract </link:label>
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<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4a1ed922-f95b-4690-b9bb-df9784dc506f_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets by Major Class [Axis] </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets by Major Class [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_047433cf-7ed0-4876-9730-eb2ad756f042_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total equity </link:label>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_cd4e7a28-a441-4b9e-b3a8-8d64a6573355_periodStartLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Beginning Balance </link:label>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_d59b9362-7788-403e-b608-6a1a4c907735_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ending Balance </link:label>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_c96a2c3f-7913-4a0c-983b-b137363d1200_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative adjustment amount to decrease retained earnings </link:label>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
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<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent_960667a8-1362-4ed2-af8a-737c516c13ed_terseLabel_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases (2) </link:label>
<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent_label_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease And Finance Lease Liability, Current </link:label>
<link:label id="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent_documentation_en-US" xlink:label="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Operating Lease And Finance Lease Liability, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:href="aon-20211231.xsd#aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:to="lab_aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_dei_AmendmentFlag_1339a928-e49b-43d9-882c-d803c8ac882e_terseLabel_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amendment Flag </link:label>
<link:label id="lab_dei_AmendmentFlag_label_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amendment Flag </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AmendmentFlag"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AmendmentFlag" xlink:to="lab_dei_AmendmentFlag" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebt_1a22137b-15df-4bb2-874a-e8ebea668ce8_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Issuance of debt </link:label>
<link:label id="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebt_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Proceeds from Issuance of Long-term Debt </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementEquityComponentsAxis_79cc2269-d4b1-4c79-b8b7-3e1c6f1c5e0c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Components [Axis] </link:label>
<link:label id="lab_us-gaap_StatementEquityComponentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity Components [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueDisclosuresAbstract_169a1ec7-46f5-4016-8d5b-3e6296eddcd3_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Disclosures [Abstract] </link:label>
<link:label id="lab_us-gaap_FairValueDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value Disclosures [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract" xlink:to="lab_us-gaap_FairValueDisclosuresAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ContractWithCustomerAssetNetNoncurrent_264148e0-5ca3-48f0-8029-89f59f630657_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Costs to obtain contracts with customers </link:label>
<link:label id="lab_us-gaap_ContractWithCustomerAssetNetNoncurrent_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:to="lab_us-gaap_ContractWithCustomerAssetNetNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DisaggregationOfRevenueTable_f0702900-114a-4de3-a9db-0d882bb3cded_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue [Table] </link:label>
<link:label id="lab_us-gaap_DisaggregationOfRevenueTable_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disaggregation of Revenue [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable" xlink:to="lab_us-gaap_DisaggregationOfRevenueTable" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears_e67dc4f3-0318-4ea6-880a-d623349927d7_terseLabel_en-US" xlink:label="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Expected future benefit payments 2026 – 2030 </link:label>
<link:label id="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears_label_en-US" xlink:label="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, after Year Four For Next Four Years </link:label>
<link:label id="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears_documentation_en-US" xlink:label="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Expected Future Benefit Payment, after Year Four For Next Four Years </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:href="aon-20211231.xsd#aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:to="lab_aon_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFourForNextFourYears" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_80a7e7a2-61f2-4334-9a1f-cd2172ca3f20_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Actual allocation percentage </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:to="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxAssetsLeaseLiability_f6036bf2-9726-44d6-ab6c-f77b351c8feb_terseLabel_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease liabilities </link:label>
<link:label id="lab_aon_DeferredTaxAssetsLeaseLiability_label_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Lease Liability </link:label>
<link:label id="lab_aon_DeferredTaxAssetsLeaseLiability_documentation_en-US" xlink:label="lab_aon_DeferredTaxAssetsLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Lease Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxAssetsLeaseLiability" xlink:href="aon-20211231.xsd#aon_DeferredTaxAssetsLeaseLiability"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxAssetsLeaseLiability" xlink:to="lab_aon_DeferredTaxAssetsLeaseLiability" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6054e4b8-b283-4782-a02c-df191b29b01f_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair value of assets and liabilities [Line Items] </link:label>
<link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CreditFacilityExpiringFebruary2022Member_5d024388-ac39-4930-9ba7-3da790772add_terseLabel_en-US" xlink:label="lab_aon_CreditFacilityExpiringFebruary2022Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring February 2022 </link:label>
<link:label id="lab_aon_CreditFacilityExpiringFebruary2022Member_label_en-US" xlink:label="lab_aon_CreditFacilityExpiringFebruary2022Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring February 2022 [Member] </link:label>
<link:label id="lab_aon_CreditFacilityExpiringFebruary2022Member_documentation_en-US" xlink:label="lab_aon_CreditFacilityExpiringFebruary2022Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Credit Facility Expiring February 2022 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CreditFacilityExpiringFebruary2022Member" xlink:href="aon-20211231.xsd#aon_CreditFacilityExpiringFebruary2022Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CreditFacilityExpiringFebruary2022Member" xlink:to="lab_aon_CreditFacilityExpiringFebruary2022Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_a1d11a4d-71ea-4564-8b28-2a2193f5775b_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Thereafter </link:label>
<link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Operating Lease, Liability, to be Paid, after Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_2622ef50-ebe6-4b42-8f12-e583f43fb636_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrealized gain recognized in AOCI </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax"/>
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<link:label id="lab_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_f7540723-a8ba-4d16-abd7-2e881617adec_terseLabel_en-US" xlink:label="lab_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase in valuation allowance </link:label>
<link:label id="lab_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_label_en-US" xlink:label="lab_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount"/>
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<link:label id="lab_srt_ProductOrServiceAxis_3061372e-6900-4acc-b8f8-ec7a8eeaaafd_terseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Product and Service [Axis] </link:label>
<link:label id="lab_srt_ProductOrServiceAxis_label_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Product and Service [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductOrServiceAxis" xlink:to="lab_srt_ProductOrServiceAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_a10876b7-143a-49f4-b2d7-8a7ca37c997f_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance for Credit Loss [Roll Forward] </link:label>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance for Credit Loss [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityPublicFloat_a6424ea3-a76c-4988-8e9e-4f3e8f35de12_terseLabel_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Public Float </link:label>
<link:label id="lab_dei_EntityPublicFloat_label_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Public Float </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityPublicFloat"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityPublicFloat" xlink:to="lab_dei_EntityPublicFloat" xlink:type="arc" order="1"/>
<link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_e5557206-2f18-4d5d-ba81-b5983b586005_terseLabel_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Documents Incorporated by Reference </link:label>
<link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_label_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Documents Incorporated by Reference [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:to="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShortTermLeaseCost_63a2e03c-3db3-49b1-8d69-419fde123677_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term lease cost </link:label>
<link:label id="lab_us-gaap_ShortTermLeaseCost_label_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Lease, Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermLeaseCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermLeaseCost" xlink:to="lab_us-gaap_ShortTermLeaseCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_e5a05442-19aa-41f1-bc9f-40d9ee6639ff_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares issued — employee stock compensation plans (in shares) </link:label>
<link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_ab825983-86ff-4b7c-87c5-015233939fde_verboseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares issued (in shares) </link:label>
<link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GuaranteeObligationsNatureDomain_28164c8e-fb69-44b2-9331-b43274d8811a_terseLabel_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsNatureDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Nature [Domain] </link:label>
<link:label id="lab_us-gaap_GuaranteeObligationsNatureDomain_label_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsNatureDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Nature [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain" xlink:to="lab_us-gaap_GuaranteeObligationsNatureDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_a31c7c3b-0c3b-4338-81ba-ded4e36eb03c_terseLabel_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Discontinued Operations, Disposed of by Sale </link:label>
<link:label id="lab_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_label_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Discontinued Operations, Disposed of by Sale [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:to="lab_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockRepurchasedDuringPeriodShares_1734c33f-3773-4b98-ba33-55d3d369fc6e_negatedLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares purchased (in shares) </link:label>
<link:label id="lab_us-gaap_StockRepurchasedDuringPeriodShares_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stock Repurchased During Period, Shares </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedDuringPeriodShares" xlink:to="lab_us-gaap_StockRepurchasedDuringPeriodShares" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_dd69173e-c3c4-4148-b6b9-21f2bad1c3c4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency translation adjustments </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_240a22ac-fbd6-45a6-b116-0736d809ab10_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net foreign currency translation adjustments </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementLineItems_fdd0734d-aeb3-4039-8240-20d81593e45c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement [Line Items] </link:label>
<link:label id="lab_us-gaap_StatementLineItems_label_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems" xlink:to="lab_us-gaap_StatementLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A260SeniorNotesDueDecember2031Member_167b4817-274a-4e5c-b521-7484a2842663_terseLabel_en-US" xlink:label="lab_aon_A260SeniorNotesDueDecember2031Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.60% Senior Notes due December 2031 </link:label>
<link:label id="lab_aon_A260SeniorNotesDueDecember2031Member_label_en-US" xlink:label="lab_aon_A260SeniorNotesDueDecember2031Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.60% Senior Notes Due December 2031 [Member] </link:label>
<link:label id="lab_aon_A260SeniorNotesDueDecember2031Member_documentation_en-US" xlink:label="lab_aon_A260SeniorNotesDueDecember2031Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.60% Senior Notes Due December 2031 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A260SeniorNotesDueDecember2031Member" xlink:href="aon-20211231.xsd#aon_A260SeniorNotesDueDecember2031Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A260SeniorNotesDueDecember2031Member" xlink:to="lab_aon_A260SeniorNotesDueDecember2031Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_5ec4d0bb-1ba2-43fb-a23b-7fa23e455c5d_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares issued — employee stock compensation plans </link:label>
<link:label id="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive_a346a877-f834-4b5c-94ba-102dfda320d8_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Five </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ChangeInCapitalizedContractCostsRollForward_a1b576f4-9b01-4ac5-8a7c-7d6dbf3c8e35_terseLabel_en-US" xlink:label="lab_aon_ChangeInCapitalizedContractCostsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change in Capitalized Contract Costs </link:label>
<link:label id="lab_aon_ChangeInCapitalizedContractCostsRollForward_label_en-US" xlink:label="lab_aon_ChangeInCapitalizedContractCostsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change In Capitalized Contract Costs [Roll Forward] </link:label>
<link:label id="lab_aon_ChangeInCapitalizedContractCostsRollForward_documentation_en-US" xlink:label="lab_aon_ChangeInCapitalizedContractCostsRollForward" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change In Capitalized Contract Costs [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ChangeInCapitalizedContractCostsRollForward" xlink:href="aon-20211231.xsd#aon_ChangeInCapitalizedContractCostsRollForward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ChangeInCapitalizedContractCostsRollForward" xlink:to="lab_aon_ChangeInCapitalizedContractCostsRollForward" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_RetirementPlanTypeDomain_de1001f2-90c9-4d03-9dbf-188d00f874d7_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Type [Domain] </link:label>
<link:label id="lab_us-gaap_RetirementPlanTypeDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Plan Type [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanTypeDomain" xlink:to="lab_us-gaap_RetirementPlanTypeDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DomesticCountryMember_8aa20625-21ae-452c-a865-1b3409fd3316_terseLabel_en-US" xlink:label="lab_us-gaap_DomesticCountryMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.K. </link:label>
<link:label id="lab_us-gaap_DomesticCountryMember_label_en-US" xlink:label="lab_us-gaap_DomesticCountryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Domestic Tax Authority [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DomesticCountryMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DomesticCountryMember" xlink:to="lab_us-gaap_DomesticCountryMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AlternativeInvestmentsMember_1e4308ee-6919-4818-8263-b4b9b0b16c85_terseLabel_en-US" xlink:label="lab_aon_AlternativeInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Alternative investments </link:label>
<link:label id="lab_aon_AlternativeInvestmentsMember_label_en-US" xlink:label="lab_aon_AlternativeInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Alternative Investments [Member] </link:label>
<link:label id="lab_aon_AlternativeInvestmentsMember_documentation_en-US" xlink:label="lab_aon_AlternativeInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds, and any other investment. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AlternativeInvestmentsMember" xlink:href="aon-20211231.xsd#aon_AlternativeInvestmentsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AlternativeInvestmentsMember" xlink:to="lab_aon_AlternativeInvestmentsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations_283ee81a-29eb-4cef-8812-fd103f0d4ff1_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension, other postretirement and postemployment liabilities </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations" xlink:to="lab_us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtDisclosureAbstract_76f446b2-ee9c-4c3a-9086-83c1f20eefed_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Disclosure [Abstract] </link:label>
<link:label id="lab_us-gaap_DebtDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureAbstract" xlink:to="lab_us-gaap_DebtDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0e21e3aa-5d57-4ecc-bbe5-0efdc555888e_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Property, Plant and Equipment, Type [Axis] </link:label>
<link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-Lived Tangible Asset [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_973e7d35-6381-450a-bfdf-b501a6b0acd4_negatedLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Valuation allowance on deferred tax assets </link:label>
<link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Valuation Allowance </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation_efd4d02d-fdf9-431d-808e-588166d7a972_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plans with PBO in excess of plan assets, PBO </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_b79bb2d9-0fb3-4b01-90e9-19af0b70fcac_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Employee Benefits </link:label>
<link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Retirement Benefits [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:to="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_7ffdd0b0-97a0-4a0d-a8ab-9f60832b6427_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Business Acquisitions, by Acquisition [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Business Acquisitions, by Acquisition [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="arc" order="1"/>
<link:label id="lab_dei_DocumentAnnualReport_1093b3af-dc0b-4817-b9e5-7353d52a2232_terseLabel_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Annual Report </link:label>
<link:label id="lab_dei_DocumentAnnualReport_label_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Document Annual Report </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentAnnualReport"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentAnnualReport" xlink:to="lab_dei_DocumentAnnualReport" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GovernmentBondSecuritiesMember_ee477412-afba-4ecc-a7f8-466f21d1da5d_terseLabel_en-US" xlink:label="lab_aon_GovernmentBondSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Government bonds </link:label>
<link:label id="lab_aon_GovernmentBondSecuritiesMember_label_en-US" xlink:label="lab_aon_GovernmentBondSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Government Bond Securities [Member] </link:label>
<link:label id="lab_aon_GovernmentBondSecuritiesMember_documentation_en-US" xlink:label="lab_aon_GovernmentBondSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> This category includes information about long-term debt securities that are issued by either a domestic or foreign government business entity with a date certain promise of repayment and a return to the holder for the time value of money. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GovernmentBondSecuritiesMember" xlink:href="aon-20211231.xsd#aon_GovernmentBondSecuritiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GovernmentBondSecuritiesMember" xlink:to="lab_aon_GovernmentBondSecuritiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_22694d9b-bd18-4e1a-b9f4-ccbe5e8b0772_negatedLabel_en-US" xlink:label="lab_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill related to disposals </link:label>
<link:label id="lab_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_label_en-US" xlink:label="lab_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill, Written off Related to Sale of Business Unit </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:to="lab_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_e6123bec-3ec7-4d42-8949-47695f81a32e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months </link:label>
<link:label id="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_label_en-US" xlink:label="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:to="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_Assets_67921307-2cb5-458b-9ca2-efafcc887402_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total assets </link:label>
<link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAccruedLiabilitiesNoncurrent_0167d646-5da9-4f5e-aae0-3489c118d6bf_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_OtherAccruedLiabilitiesNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Accrued Liabilities, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAccruedLiabilitiesNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:to="lab_us-gaap_OtherAccruedLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment_496a66bc-7083-4f39-84d7-21f90ac69c9a_negatedLabel_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Intangibles and property, plant and equipment </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment_label_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities Intangible Assets and Property Plant and Equipment </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment_documentation_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill and from property, plant, and equipment. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:href="aon-20211231.xsd#aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:to="lab_aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PlanNameDomain_9d118217-ec8e-43b2-9177-408734ab5cec_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plan Name [Domain] </link:label>
<link:label id="lab_us-gaap_PlanNameDomain_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Plan Name [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_6334d45a-da28-4154-ab4e-24e732a684c4_terseLabel_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax liabilities: </link:label>
<link:label id="lab_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_label_en-US" xlink:label="lab_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Deferred Tax Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:to="lab_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock_c8ff868e-7a74-4056-8983-03a1be10aa4e_terseLabel_en-US" xlink:label="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Components of Fixed Assets, Net </link:label>
<link:label id="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock_label_en-US" xlink:label="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Property, Plant and Equipment Components [Table Text Block] </link:label>
<link:label id="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock_documentation_en-US" xlink:label="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Tabular disclosure of the components of property, plant and equipment. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:href="aon-20211231.xsd#aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:to="lab_aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_InterestPaidNet_073e5a29-0c03-438a-8449-a7abf24774e4_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest paid </link:label>
<link:label id="lab_us-gaap_InterestPaidNet_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Interest Paid, Excluding Capitalized Interest, Operating Activities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPaidNet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet" xlink:to="lab_us-gaap_InterestPaidNet" xlink:type="arc" order="1"/>
<link:label id="lab_srt_SegmentGeographicalDomain_c0c205b6-122c-4c81-9f85-3d9163352561_terseLabel_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Geographical [Domain] </link:label>
<link:label id="lab_srt_SegmentGeographicalDomain_label_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Geographical [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SegmentGeographicalDomain" xlink:to="lab_srt_SegmentGeographicalDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments_dad8d49c-5cff-47c4-ad4a-c0e6c99e7225_totalLabel_en-US" xlink:label="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net periodic benefit (income) cost </link:label>
<link:label id="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments_label_en-US" xlink:label="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Net Periodic Benefit Cost Before Recognized Net Gain (Loss) Due to Settlements and Curtailments </link:label>
<link:label id="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments_documentation_en-US" xlink:label="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Net Periodic Benefit Cost Before Recognized Net Gain (Loss) Due to Settlements and Curtailments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:href="aon-20211231.xsd#aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:to="lab_aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NoncontrollingInterestMember_320b2fb4-eced-48e3-86fd-deaebee9d91c_terseLabel_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Non-controlling Interests </link:label>
<link:label id="lab_us-gaap_NoncontrollingInterestMember_label_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Noncontrolling Interest [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncontrollingInterestMember" xlink:to="lab_us-gaap_NoncontrollingInterestMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeContractTypeDomain_1ed608a9-7038-4ad4-bb71-9449d7ecfdc7_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeContractTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative, Name [Domain] </link:label>
<link:label id="lab_us-gaap_DerivativeContractTypeDomain_label_en-US" xlink:label="lab_us-gaap_DerivativeContractTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Contract [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeContractTypeDomain" xlink:to="lab_us-gaap_DerivativeContractTypeDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_10223aa4-bab4-4197-8c6b-b8b89c00c0c7_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized prior-service cost </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_a220cac7-3182-4135-a1cd-caf9c7dedaa4_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Prior service cost (income) </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_d828e741-ba59-4edd-bd51-8f6bd37a2e0a_netLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized prior-service credit </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A4.00SeniorNotesDueNovember2023Member_873e011a-2f40-45c4-9266-28ecbdfccd42_terseLabel_en-US" xlink:label="lab_aon_A4.00SeniorNotesDueNovember2023Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.00% Senior Notes due November 2023 </link:label>
<link:label id="lab_aon_A4.00SeniorNotesDueNovember2023Member_label_en-US" xlink:label="lab_aon_A4.00SeniorNotesDueNovember2023Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.00% Senior Notes Due November 2023 [Member] </link:label>
<link:label id="lab_aon_A4.00SeniorNotesDueNovember2023Member_documentation_en-US" xlink:label="lab_aon_A4.00SeniorNotesDueNovember2023Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 4.00% Senior Notes Due November 2023 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A4.00SeniorNotesDueNovember2023Member" xlink:href="aon-20211231.xsd#aon_A4.00SeniorNotesDueNovember2023Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A4.00SeniorNotesDueNovember2023Member" xlink:to="lab_aon_A4.00SeniorNotesDueNovember2023Member" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent_c71cb89c-2f71-4eb2-ae6e-68a248fb143f_terseLabel_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capital Losses </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent_label_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Capital Losses, Percent </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent_documentation_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Capital Losses, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:href="aon-20211231.xsd#aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:to="lab_aon_EffectiveIncomeTaxRateReconciliationCapitalLossesPercent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_75c3d658-29b5-41ff-9be4-1402ed5ea680_terseLabel_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Summary of Significant Accounting Principles and Practices </link:label>
<link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_label_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Significant Accounting Policies [Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SignificantAccountingPoliciesTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionDomain_f2649b9c-7d39-4e32-9093-259f353c6a0f_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption [Domain] </link:label>
<link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionDomain_label_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cumulative Effect, Period of Adoption [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:to="lab_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShortTermBorrowings_8dc77bca-5622-4f3c-9ff9-0f39396f82d3_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermBorrowings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial paper outstanding </link:label>
<link:label id="lab_us-gaap_ShortTermBorrowings_label_en-US" xlink:label="lab_us-gaap_ShortTermBorrowings" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Short-term Debt </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermBorrowings" xlink:to="lab_us-gaap_ShortTermBorrowings" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_c2636108-523e-4730-827d-035fe4ff45b8_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash provided by operating activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_be3979bd-ed4d-41c5-b564-b0e8117a23f5_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash provided by operating activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Operating Activities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
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<link:label id="lab_us-gaap_LitigationStatusAxis_67106f15-14d6-48b3-92aa-623e14827c3c_terseLabel_en-US" xlink:label="lab_us-gaap_LitigationStatusAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Status [Axis] </link:label>
<link:label id="lab_us-gaap_LitigationStatusAxis_label_en-US" xlink:label="lab_us-gaap_LitigationStatusAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Litigation Status [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LitigationStatusAxis" xlink:to="lab_us-gaap_LitigationStatusAxis" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_4047c06a-cbac-44e6-951a-2bc97f616352_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Summary of Outstanding Debt </link:label>
<link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Debt [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDebtTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_91f0eea5-c037-4a42-bf11-0c4e6e39aed0_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Recurring and Nonrecurring [Table] </link:label>
<link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Recurring and Nonrecurring [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentTable_829410a1-4b92-4b04-a31a-3a634e9c7caf_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Long-term Debt Instruments [Table] </link:label>
<link:label id="lab_us-gaap_DebtInstrumentTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Long-term Debt Instruments [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTable" xlink:to="lab_us-gaap_DebtInstrumentTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAssetsMiscellaneousCurrent_c3196f0e-3954-4ffd-addc-a016b7f38d0f_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsMiscellaneousCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_OtherAssetsMiscellaneousCurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsMiscellaneousCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Assets, Miscellaneous, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMiscellaneousCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMiscellaneousCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsMiscellaneousCurrent" xlink:to="lab_us-gaap_OtherAssetsMiscellaneousCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CapitalizedContractCostAxis_d2d36547-ae02-49bd-9ce6-0b8013427250_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost [Axis] </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostAxis_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost [Axis] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalizedContractCostAxis"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostAxis" xlink:to="lab_us-gaap_CapitalizedContractCostAxis" xlink:type="arc" order="1"/>
<link:label id="lab_aon_CommercialRiskSolutionsMember_3825a380-6f72-4ce2-8c70-9f93e48b5409_terseLabel_en-US" xlink:label="lab_aon_CommercialRiskSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial Risk Solutions </link:label>
<link:label id="lab_aon_CommercialRiskSolutionsMember_label_en-US" xlink:label="lab_aon_CommercialRiskSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial Risk Solutions [Member] </link:label>
<link:label id="lab_aon_CommercialRiskSolutionsMember_documentation_en-US" xlink:label="lab_aon_CommercialRiskSolutionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Commercial Risk Solutions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_CommercialRiskSolutionsMember" xlink:href="aon-20211231.xsd#aon_CommercialRiskSolutionsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_CommercialRiskSolutionsMember" xlink:to="lab_aon_CommercialRiskSolutionsMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_AnnuitiesMember_a6ab69d1-d30c-4bce-9b57-098ebc5b34a2_terseLabel_en-US" xlink:label="lab_aon_AnnuitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Annuities </link:label>
<link:label id="lab_aon_AnnuitiesMember_label_en-US" xlink:label="lab_aon_AnnuitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Annuities [Member] </link:label>
<link:label id="lab_aon_AnnuitiesMember_documentation_en-US" xlink:label="lab_aon_AnnuitiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents fixed income investments in annuities. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_AnnuitiesMember" xlink:href="aon-20211231.xsd#aon_AnnuitiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_AnnuitiesMember" xlink:to="lab_aon_AnnuitiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense_51c48422-f459-4e8b-a667-7ca468b03bc8_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Nondeductible expenses </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_337c6e9a-306c-418e-aa96-f655b835c6d3_verboseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average ordinary shares outstanding - basic (in shares) </link:label>
<link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_3dc66034-235e-4ccd-8701-40acdd8427df_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Basic weighted average ordinary shares outstanding (in shares) </link:label>
<link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted Average Number of Shares Outstanding, Basic </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EarningsPerShareDiluted_3dffbb5e-47aa-4404-8e4d-1b4faa583aa4_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Diluted net income per share attributable to Aon shareholders (in dollars per share) </link:label>
<link:label id="lab_us-gaap_EarningsPerShareDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Earnings Per Share, Diluted </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareDiluted" xlink:to="lab_us-gaap_EarningsPerShareDiluted" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings_3d8c0e90-f227-4ba5-9f79-a9b4c085f003_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax adjustments, international earnings </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationRepatriationOfForeignEarnings" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_570a2938-e9b1-4ffb-93c5-0969affbc8ab_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Service cost </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Service Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:to="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_ca4b8494-516d-484f-970d-fc7bc84b3f5b_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized loss </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_0acc64c4-7124-460b-8d22-254714124090_negatedNetLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedNetLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net loss </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
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<link:label id="lab_us-gaap_SalesMember_fa51a1e2-615a-4580-9fcb-7298a0c2427f_terseLabel_en-US" xlink:label="lab_us-gaap_SalesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total revenue </link:label>
<link:label id="lab_us-gaap_SalesMember_label_en-US" xlink:label="lab_us-gaap_SalesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Sales [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesMember"/>
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<link:label id="lab_us-gaap_IncomeTaxesPaidNet_3174763e-5993-4c9a-aced-20d62cab2517_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income taxes paid, net of refunds </link:label>
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<link:label id="lab_us-gaap_AccountingStandardsUpdateExtensibleList_2c8e7ffa-a246-478b-bca8-255655db777e_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingStandardsUpdateExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounting Standards Update [Extensible Enumeration] </link:label>
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<link:label id="lab_aon_A2875SeniorNotesDueMay2026Member_5341b7a1-bde7-4782-8ca8-9b4b9783a512_terseLabel_en-US" xlink:label="lab_aon_A2875SeniorNotesDueMay2026Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.875% Senior Notes due May 2026 (EUR 500M) </link:label>
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<link:label id="lab_aon_A2875SeniorNotesDueMay2026Member_documentation_en-US" xlink:label="lab_aon_A2875SeniorNotesDueMay2026Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.875% Senior Notes Due May 2026 </link:label>
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<link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_82b9202d-b469-4377-a668-df366d87e507_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Intangible assets, net </link:label>
<link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_1ebdc58a-fe34-4e42-a308-8768feff9f5a_totalLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Carrying Amount </link:label>
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<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:to="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_a15b35db-0c86-4736-b396-d85698d434e7_totalLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Comprehensive income attributable to Aon shareholders </link:label>
<link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Comprehensive Income (Loss), Net of Tax, Attributable to Parent </link:label>
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<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="arc" order="1"/>
<link:label id="lab_aon_PaymentsForProceedsFromMarketableSecurities_16c759b7-4707-4c7f-a2e2-eedd22679b5c_negatedLabel_en-US" xlink:label="lab_aon_PaymentsForProceedsFromMarketableSecurities" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net sales (purchases) of short-term investments - non fiduciary </link:label>
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<link:label id="lab_aon_PaymentsForProceedsFromMarketableSecurities_documentation_en-US" xlink:label="lab_aon_PaymentsForProceedsFromMarketableSecurities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The cash inflow or outflow from sales or purchases of marketable securities. </link:label>
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<link:label id="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans_52b63eaa-e26d-404f-91d4-43b093fdaeb6_terseLabel_en-US" xlink:label="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unamortized expense, based on current performance levels </link:label>
<link:label id="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans_label_en-US" xlink:label="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unamortized Expense on Performance Based Plans </link:label>
<link:label id="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans_documentation_en-US" xlink:label="lab_aon_UnamortizedExpenseOnPerformanceBasedPlans" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents unamortized expense of performance-based stock award plans, based on current performance levels. </link:label>
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<link:label id="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member_00c3eb32-d55a-42f9-9554-dc199f08c199_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 4.75% Senior Notes due 2045 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.750 Senior Notes Due 2045 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4750SeniorNotesDue2045Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.750 Senior Notes Due 2045 </link:label>
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<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_59face6e-2e66-40b5-9a1b-2a8d1514d74e_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other comprehensive income (loss), net of tax: </link:label>
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<link:label id="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_3389a5c9-d6c3-4c77-afc6-f6e9702826ab_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Amounts Recognized in the Consolidated Statements of Financial Position </link:label>
<link:label id="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Amounts Recognized in Balance Sheet [Table Text Block] </link:label>
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<link:label id="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet_c3c1c08c-22a8-4451-9ba5-9e8be354c4e7_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax liabilities </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet_29c886db-52d0-4ff9-9164-9b0cdf80ff85_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax liabilities — non-current </link:label>
<link:label id="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Tax Liabilities, Net </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
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<link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_d8870633-4856-4111-9806-dbc0b5575ea4_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition, Acquiree [Domain] </link:label>
<link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Acquisition, Acquiree [Domain] </link:label>
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<link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_5257c566-de87-4ae6-9946-7bfa7ca3ca68_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Decrease of net loss from discontinued operations </link:label>
<link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest </link:label>
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<link:label id="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_b3f0963d-edff-4b4d-9a0e-844d64ca8c65_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reconciliation of the Income Tax Provisions based on the U.S. Statutory Corporate Tax Rate to the Provisions Reflected in the Consolidated Financial Statements </link:label>
<link:label id="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] </link:label>
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<link:label id="lab_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_63fd0abd-aa25-47a0-bc1b-19a3cee73e58_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Assets and Liabilities that are Measured at Fair Value on a Recurring Basis </link:label>
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<link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld_2a3fae41-7333-46bd-b2ea-56fdd72fb94b_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Relating to assets still held at the end of the year </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld" xlink:to="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeld" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ForWelfareSrlMember_6de7be23-0d53-410a-b63c-5267b0fa3f1b_terseLabel_en-US" xlink:label="lab_aon_ForWelfareSrlMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> For Welfare S.r.l </link:label>
<link:label id="lab_aon_ForWelfareSrlMember_label_en-US" xlink:label="lab_aon_ForWelfareSrlMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> For Welfare S.r.l [Member] </link:label>
<link:label id="lab_aon_ForWelfareSrlMember_documentation_en-US" xlink:label="lab_aon_ForWelfareSrlMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> For Welfare S.r.l </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ForWelfareSrlMember" xlink:href="aon-20211231.xsd#aon_ForWelfareSrlMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ForWelfareSrlMember" xlink:to="lab_aon_ForWelfareSrlMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_4a47d05b-c799-48a6-a8a8-d071195da2fe_totalLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based compensation expense, net of tax </link:label>
<link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Expense, after Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0447684d-6bce-46a3-b9ad-f21782890aee_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accumulated Other Comprehensive Loss, Net of Tax </link:label>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_7313da8a-8e0e-4b1b-b241-11792ed4fc09_verboseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> AOCI attributable to parent </link:label>
<link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> AOCI Attributable to Parent [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_MarketingTechnologyAndOtherMember_3e386afd-71af-49d1-84f0-80ca6dcaa8dd_terseLabel_en-US" xlink:label="lab_aon_MarketingTechnologyAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Technology and other </link:label>
<link:label id="lab_aon_MarketingTechnologyAndOtherMember_label_en-US" xlink:label="lab_aon_MarketingTechnologyAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Marketing Technology and Other [Member] </link:label>
<link:label id="lab_aon_MarketingTechnologyAndOtherMember_documentation_en-US" xlink:label="lab_aon_MarketingTechnologyAndOtherMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents finite-lived intangible assets related to marketing and technology. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_MarketingTechnologyAndOtherMember" xlink:href="aon-20211231.xsd#aon_MarketingTechnologyAndOtherMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_MarketingTechnologyAndOtherMember" xlink:to="lab_aon_MarketingTechnologyAndOtherMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermInvestments_a4867a1a-37f3-4f47-ab4d-17d9ddbcb6d9_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Investments </link:label>
<link:label id="lab_us-gaap_LongTermInvestments_label_en-US" xlink:label="lab_us-gaap_LongTermInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Investments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermInvestments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermInvestments" xlink:to="lab_us-gaap_LongTermInvestments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cedd5976-4c81-43a6-9cc1-03e40d60e490_terseLabel_en-US" xlink:label="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial Instruments [Domain] </link:label>
<link:label id="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_label_en-US" xlink:label="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financial Instruments [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome_cb727e42-114c-49f4-ad60-e4f0b2d89372_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Present value of lease liabilities </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Net Of Sublease Income </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Net Of Sublease Income </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_eb517506-7af9-4a2f-b05f-bc25006f026a_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gain (loss) recognized in Accumulated other comprehensive loss </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntityCentralIndexKey_2c14708f-ac98-4f38-a6d0-e898c54b5f2d_terseLabel_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Central Index Key </link:label>
<link:label id="lab_dei_EntityCentralIndexKey_label_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entity Central Index Key </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCentralIndexKey"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCentralIndexKey" xlink:to="lab_dei_EntityCentralIndexKey" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_3611cd58-a705-4f6d-a4c7-99c010a43e55_terseLabel_en-US" xlink:label="lab_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other comprehensive income (loss) before reclassifications </link:label>
<link:label id="lab_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> OCI, before Reclassifications, before Tax, Attributable to Parent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent" xlink:to="lab_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_f1b19be7-21e5-4e5d-b240-e9d77a069062_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Settlements </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanSettlementsBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LeaseCost_f6542844-84d1-4287-976b-9da94b6fcfdc_totalLabel_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net lease cost </link:label>
<link:label id="lab_us-gaap_LeaseCost_label_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lease, Cost </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCost"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCost" xlink:to="lab_us-gaap_LeaseCost" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_aed00e85-9a2e-493e-a048-c5d562c98c0a_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Equity </link:label>
<link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract"/>
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<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions_f692be51-a004-4f7a-be03-6848978dd1ec_negatedLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Reductions for tax positions of prior years </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions"/>
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<link:label id="lab_us-gaap_LossContingenciesLineItems_912b8130-ee09-4885-9474-b11d6068fa4f_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingencies [Line Items] </link:label>
<link:label id="lab_us-gaap_LossContingenciesLineItems_label_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Loss Contingencies [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesLineItems" xlink:to="lab_us-gaap_LossContingenciesLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_ba6df9fb-1b7f-4425-9b8b-8fe681ea00ff_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other non-current liabilities </link:label>
<link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_7067281a-9d73-4d9a-811b-f7af1d648550_totalLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other non-current liabilities </link:label>
<link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Liabilities, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:to="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_c78d26a8-4cd1-47ba-b70b-74ea79b2d250_periodStartLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the beginning of the Period </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_6d2afdbe-8334-4d6b-8f79-b1039a744d03_periodEndLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Balance at the end of the period </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Benefit Obligation </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:type="arc" order="1"/>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree_a2a1f133-7ee3-49ef-afd5-5e9201966fae_totalLabel_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2024 </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree_label_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Three </link:label>
<link:label id="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree_documentation_en-US" xlink:label="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Financing And Operating Lease Liability, Payments, Net Of Sublease Income, Due Year Three </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:href="aon-20211231.xsd#aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:to="lab_aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_TreasuryStockSharesAcquired_3a745f59-b81b-453f-a54a-5c7c3ea01472_terseLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockSharesAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of shares repurchased (in shares) </link:label>
<link:label id="lab_us-gaap_TreasuryStockSharesAcquired_label_en-US" xlink:label="lab_us-gaap_TreasuryStockSharesAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Shares, Acquired </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockSharesAcquired"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockSharesAcquired" xlink:to="lab_us-gaap_TreasuryStockSharesAcquired" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock_001b868c-bfc1-4978-b587-0e3e392f45f1_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Commercial Paper </link:label>
<link:label id="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Long-term Debt Instruments [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDebtInstrumentsTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentLineItems_e8cd44ed-39dc-43e7-8c7d-b3304af258df_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument [Line Items] </link:label>
<link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentLineItems" xlink:to="lab_us-gaap_DebtInstrumentLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_dei_TradingSymbol_7813613d-57c9-4606-a48c-f06f51a77c8e_terseLabel_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Trading Symbol </link:label>
<link:label id="lab_dei_TradingSymbol_label_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Trading Symbol </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_TradingSymbol"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_TradingSymbol" xlink:to="lab_dei_TradingSymbol" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeAssets_a2322834-2c7e-4197-ab28-bd18f5b87264_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gross foreign exchange contracts </link:label>
<link:label id="lab_us-gaap_DerivativeAssets_label_en-US" xlink:label="lab_us-gaap_DerivativeAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Asset </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeAssets" xlink:to="lab_us-gaap_DerivativeAssets" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesOther_0654d79a-089b-4e4c-b112-f1182107266c_negatedLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_us-gaap_DeferredTaxLiabilitiesOther_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Other </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesOther" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OtherCountryMember_b874dc66-a901-47ae-83e9-c79a20b90280_terseLabel_en-US" xlink:label="lab_aon_OtherCountryMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other </link:label>
<link:label id="lab_aon_OtherCountryMember_label_en-US" xlink:label="lab_aon_OtherCountryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Country [Member] </link:label>
<link:label id="lab_aon_OtherCountryMember_documentation_en-US" xlink:label="lab_aon_OtherCountryMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Information pertaining to all other income tax authorities outside of the U.S. and the U.K. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OtherCountryMember" xlink:href="aon-20211231.xsd#aon_OtherCountryMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OtherCountryMember" xlink:to="lab_aon_OtherCountryMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherCurrentLiabilitiesMember_5f6ac26c-29d7-48d3-9ae8-beae1e5c2333_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCurrentLiabilitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Current Liabilities </link:label>
<link:label id="lab_us-gaap_OtherCurrentLiabilitiesMember_label_en-US" xlink:label="lab_us-gaap_OtherCurrentLiabilitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Current Liabilities [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCurrentLiabilitiesMember" xlink:to="lab_us-gaap_OtherCurrentLiabilitiesMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies_3386994e-babc-415f-8105-0456c309543c_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change in uncertain tax positions </link:label>
<link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Tax Contingency, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCreditFacilityTable_9c0d1b65-b272-47c2-a5d1-2fc98b094018_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility [Table] </link:label>
<link:label id="lab_us-gaap_LineOfCreditFacilityTable_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityTable" xlink:to="lab_us-gaap_LineOfCreditFacilityTable" xlink:type="arc" order="1"/>
<link:label id="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_65ba5805-1dc2-43eb-ac4f-4e9b0a1594dd_totalLabel_en-US" xlink:label="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total assets acquired </link:label>
<link:label id="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_label_en-US" xlink:label="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets Acquired Including Goodwill </link:label>
<link:label id="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_documentation_en-US" xlink:label="lab_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Assets Acquired Including Goodwill </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" xlink:href="aon-20211231.xsd#aon_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill"/>
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<link:label id="lab_us-gaap_LessorLeasesPolicyTextBlock_ca015ed2-4950-4f3b-98cf-e8cf85bc623b_terseLabel_en-US" xlink:label="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases </link:label>
<link:label id="lab_us-gaap_LessorLeasesPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessor, Leases [Policy Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeasesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LessorLeasesPolicyTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorLeasesPolicyTextBlock" xlink:to="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LongTermDebtNoncurrent_03c74a84-058d-4fee-a165-bab012a8aa95_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term debt </link:label>
<link:label id="lab_us-gaap_LongTermDebtNoncurrent_f290e512-4a7b-4180-9be8-a44bca448955_netLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total long-term debt </link:label>
<link:label id="lab_us-gaap_LongTermDebtNoncurrent_6f844122-8246-4c43-b14b-1086fe11531d_verboseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term debt </link:label>
<link:label id="lab_us-gaap_LongTermDebtNoncurrent_label_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Long-term Debt, Excluding Current Maturities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
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<link:label id="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_b4cdf361-eff0-4909-8e26-4548f029b5d9_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities </link:label>
<link:label id="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities, Fair Value Disclosure [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:to="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_fa969522-011a-4ec9-9d93-efbcdaf3c8ab_terseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total share-based compensation expense </link:label>
<link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Payment Arrangement, Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_57d0ad38-1d7f-4b3a-9fac-0286fe316e4d_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred, contingent, and other consideration </link:label>
<link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Consideration Transferred, Liabilities Incurred </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred"/>
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<link:label id="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables_04792a21-7762-4004-8835-1b508873fd3a_terseLabel_en-US" xlink:label="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase in fiduciary liabilities, net of fiduciary receivables </link:label>
<link:label id="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables_label_en-US" xlink:label="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase In Fiduciary Liabilities, Net Of Fiduciary Receivables </link:label>
<link:label id="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables_documentation_en-US" xlink:label="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase In Fiduciary Liabilities, Net Of Fiduciary Receivables </link:label>
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<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables" xlink:to="lab_aon_IncreaseInFiduciaryLiabilitiesNetOfFiduciaryReceivables" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LeasesMaturityAbstract_e8a25c88-5e84-4c74-9318-56ca66a595cb_terseLabel_en-US" xlink:label="lab_aon_LeasesMaturityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_aon_LeasesMaturityAbstract_label_en-US" xlink:label="lab_aon_LeasesMaturityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases Maturity [Abstract] </link:label>
<link:label id="lab_aon_LeasesMaturityAbstract_documentation_en-US" xlink:label="lab_aon_LeasesMaturityAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Leases Maturity [Abstract] </link:label>
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<link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_8e7a6e23-7701-46ee-91c4-48c90e8ce1b9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payment for settlements </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_14910643-80e2-4059-86e6-2a801e37c0de_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Settlements </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Plan Assets, Payment for Settlement </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanSettlementsPlanAssets"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:type="arc" order="1"/>
<link:label id="lab_aon_IncomeTaxAuthorityLineItems_cc150e3f-244d-48ec-b1ef-dcabff24a0da_terseLabel_en-US" xlink:label="lab_aon_IncomeTaxAuthorityLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income taxes [Line Items] </link:label>
<link:label id="lab_aon_IncomeTaxAuthorityLineItems_label_en-US" xlink:label="lab_aon_IncomeTaxAuthorityLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Authority [Line Items] </link:label>
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<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncomeTaxAuthorityLineItems" xlink:to="lab_aon_IncomeTaxAuthorityLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_dei_EntitiesTable_d7cabcf4-2c49-48f3-a75e-d6cdd0670f38_terseLabel_en-US" xlink:label="lab_dei_EntitiesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entities [Table] </link:label>
<link:label id="lab_dei_EntitiesTable_label_en-US" xlink:label="lab_dei_EntitiesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Entities [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitiesTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntitiesTable" xlink:to="lab_dei_EntitiesTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LaborAndRelatedExpense_6bdc83d0-d6c8-4021-a2a2-0b7cecc60fc5_terseLabel_en-US" xlink:label="lab_us-gaap_LaborAndRelatedExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Compensation and benefits </link:label>
<link:label id="lab_us-gaap_LaborAndRelatedExpense_label_en-US" xlink:label="lab_us-gaap_LaborAndRelatedExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Labor and Related Expense </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LaborAndRelatedExpense"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LaborAndRelatedExpense" xlink:to="lab_us-gaap_LaborAndRelatedExpense" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ProfitLoss_d97115b3-6b21-461e-bac7-c64122ad5c50_totalLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net income </link:label>
<link:label id="lab_us-gaap_ProfitLoss_13bb1bde-5905-4889-9062-3cc63a265211_terseLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net income </link:label>
<link:label id="lab_us-gaap_ProfitLoss_label_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Income (Loss), Including Portion Attributable to Noncontrolling Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProfitLoss" xlink:to="lab_us-gaap_ProfitLoss" xlink:type="arc" order="1"/>
<link:label id="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts_66196c11-9365-4d22-898b-83c1d4f9bfed_totalLabel_en-US" xlink:label="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total costs recorded to retained earnings </link:label>
<link:label id="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts_label_en-US" xlink:label="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Value, Acquired, Cost Method Including Associated Acquisition Costs </link:label>
<link:label id="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts_documentation_en-US" xlink:label="lab_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Treasury Stock, Value, Acquired, Cost Method Including Associated Acquisition Costs </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" xlink:href="aon-20211231.xsd#aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts"/>
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<link:label id="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member_e3c791fb-0dff-4133-a0fd-99e3e9d532b1_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 4.45% Senior Notes due 2043 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.450 Senior Notes Due 2043 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 4.450 Senior Notes Due 2043 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs4450SeniorNotesDue2043Member"/>
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<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_619a3247-6e34-4a45-bd13-d9834ad8d4fb_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total liabilities assumed </link:label>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities </link:label>
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<link:label id="lab_us-gaap_ConstructionInProgressMember_888ed697-9797-400b-a9a9-ea1f670c2ae0_terseLabel_en-US" xlink:label="lab_us-gaap_ConstructionInProgressMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Construction in progress </link:label>
<link:label id="lab_us-gaap_ConstructionInProgressMember_label_en-US" xlink:label="lab_us-gaap_ConstructionInProgressMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Construction in Progress [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConstructionInProgressMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConstructionInProgressMember" xlink:to="lab_us-gaap_ConstructionInProgressMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonClassAMember_4372ed1b-8d88-45f7-a191-2437af0a7c06_terseLabel_en-US" xlink:label="lab_us-gaap_CommonClassAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Class A Ordinary Shares, $0.01 nominal value </link:label>
<link:label id="lab_us-gaap_CommonClassAMember_label_en-US" xlink:label="lab_us-gaap_CommonClassAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Class A [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonClassAMember" xlink:to="lab_us-gaap_CommonClassAMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_d9e71855-6ed9-4821-9f83-f2dd635271f5_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Ordinary shares, nominal value (in dollars per share) </link:label>
<link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_label_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Common Stock, Par or Stated Value Per Share </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GuaranteeObligationsMaximumExposure_482b8ee9-c19c-447a-b1c4-4079fdae7589_terseLabel_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsMaximumExposure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Maximum potential funding under commitments </link:label>
<link:label id="lab_us-gaap_GuaranteeObligationsMaximumExposure_label_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsMaximumExposure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantor Obligations, Maximum Exposure, Undiscounted </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GuaranteeObligationsMaximumExposure" xlink:to="lab_us-gaap_GuaranteeObligationsMaximumExposure" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems_0d8d336e-dad1-48e3-9177-50d75d6ee5c8_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan Disclosure [Line Items] </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan Disclosure [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AssetsCurrentAbstract_0a820913-0151-4884-add5-b7dc92272286_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Current assets </link:label>
<link:label id="lab_us-gaap_AssetsCurrentAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Assets, Current [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrentAbstract" xlink:to="lab_us-gaap_AssetsCurrentAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_374454db-7ec4-4663-9698-f132d8df0888_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Comprehensive Income [Abstract] </link:label>
<link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Statement of Comprehensive Income [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:to="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_039931c2-fab9-4288-9eee-5d30ce86a866_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Gross Carrying Amount </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Assets, Gross </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_9bc89798-8d26-4f9e-8505-f54337e1d6db_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Other Intangible Assets by Asset Class </link:label>
<link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Finite-Lived Intangible Assets [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare_a673b17d-153c-4d62-a3d3-cef5179aa811_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Earnings per share impact of tax holiday (in dollars per share) </link:label>
<link:label id="lab_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare_label_en-US" xlink:label="lab_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Income Tax Holiday, Income Tax Benefits Per Share </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:to="lab_us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DefinedBenefitPlanMarketRelatedValue_3b720c87-fbc3-48aa-85f2-192c757ec1aa_terseLabel_en-US" xlink:label="lab_aon_DefinedBenefitPlanMarketRelatedValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Market related value at end of year </link:label>
<link:label id="lab_aon_DefinedBenefitPlanMarketRelatedValue_label_en-US" xlink:label="lab_aon_DefinedBenefitPlanMarketRelatedValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan Market Related, Value </link:label>
<link:label id="lab_aon_DefinedBenefitPlanMarketRelatedValue_documentation_en-US" xlink:label="lab_aon_DefinedBenefitPlanMarketRelatedValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the market value of plan assets. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DefinedBenefitPlanMarketRelatedValue" xlink:href="aon-20211231.xsd#aon_DefinedBenefitPlanMarketRelatedValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DefinedBenefitPlanMarketRelatedValue" xlink:to="lab_aon_DefinedBenefitPlanMarketRelatedValue" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_InternalRevenueServiceIRSMember_66b8d9b6-8c5f-4761-9ef6-14ea2b9f1b18_terseLabel_en-US" xlink:label="lab_us-gaap_InternalRevenueServiceIRSMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> U.S. Federal </link:label>
<link:label id="lab_us-gaap_InternalRevenueServiceIRSMember_label_en-US" xlink:label="lab_us-gaap_InternalRevenueServiceIRSMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Internal Revenue Service (IRS) [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalRevenueServiceIRSMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InternalRevenueServiceIRSMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InternalRevenueServiceIRSMember" xlink:to="lab_us-gaap_InternalRevenueServiceIRSMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_LesseeWeightedAverageDiscountRateAbstract_025ccb61-a752-484b-835a-d252ffb3a104_terseLabel_en-US" xlink:label="lab_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted average discount rate </link:label>
<link:label id="lab_aon_LesseeWeightedAverageDiscountRateAbstract_label_en-US" xlink:label="lab_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Weighted Average Discount Rate [Abstract] </link:label>
<link:label id="lab_aon_LesseeWeightedAverageDiscountRateAbstract_documentation_en-US" xlink:label="lab_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lessee, Weighted Average Discount Rate [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:href="aon-20211231.xsd#aon_LesseeWeightedAverageDiscountRateAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:to="lab_aon_LesseeWeightedAverageDiscountRateAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure_33be4895-a427-4c43-8cf8-65ddc9d9511b_terseLabel_en-US" xlink:label="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Money market funds </link:label>
<link:label id="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure_label_en-US" xlink:label="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Basis Money Market Funds and Highly Liquid Securities, Fair Value Disclosure </link:label>
<link:label id="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure_documentation_en-US" xlink:label="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents the fair value of money market funds and other highly liquid securities. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:href="aon-20211231.xsd#aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:to="lab_aon_BasisMoneyMarketFundsAndHighlyLiquidSecuritiesFairValueDisclosure" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_8055609b-aad1-47d0-95bd-4a6dd25bfdd0_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total other comprehensive income (loss) </link:label>
<link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Comprehensive Income (Loss), Net of Tax </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FairValueMeasurementsRecurringMember_a7a4c170-62d7-44ac-894a-554d78b34df9_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Recurring </link:label>
<link:label id="lab_us-gaap_FairValueMeasurementsRecurringMember_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Fair Value, Recurring [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsRecurringMember" xlink:to="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_bda60622-803d-407c-8d20-14261744838b_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Liabilities assumed </link:label>
<link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_aon_OtherFinancialDataAbstract_35df121c-acea-4e0a-942c-5f1dd35db024_terseLabel_en-US" xlink:label="lab_aon_OtherFinancialDataAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Financial Data [Abstract] </link:label>
<link:label id="lab_aon_OtherFinancialDataAbstract_label_en-US" xlink:label="lab_aon_OtherFinancialDataAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Financial Data [Abstract] </link:label>
<link:label id="lab_aon_OtherFinancialDataAbstract_documentation_en-US" xlink:label="lab_aon_OtherFinancialDataAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Financial Data [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_OtherFinancialDataAbstract" xlink:href="aon-20211231.xsd#aon_OtherFinancialDataAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_OtherFinancialDataAbstract" xlink:to="lab_aon_OtherFinancialDataAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_8e82038c-6cba-479e-b2da-95c53ad97629_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] </link:label>
<link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_065b1dac-e935-422e-88b8-1cb745f582a7_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts written off, net of recoveries </link:label>
<link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounts Receivable, Allowance for Credit Loss, Writeoff </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations_d09dedd4-addd-4b7c-8d74-91b55d17a162_negatedLabel_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Lapse of statute of limitations </link:label>
<link:label id="lab_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations_label_en-US" xlink:label="lab_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:to="lab_us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_add7b12e-9613-48a6-80aa-c93926e3a23c_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2026 </link:label>
<link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Finite-Lived Intangible Asset, Expected Amortization, Year Five </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CapitalizedContractCostTableTextBlock_37b4a337-e200-4b4c-a5e9-a5a82d710baa_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost </link:label>
<link:label id="lab_us-gaap_CapitalizedContractCostTableTextBlock_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Capitalized Contract Cost [Table Text Block] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalizedContractCostTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostTableTextBlock" xlink:to="lab_us-gaap_CapitalizedContractCostTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_dei_AuditorFirmId_7fc67fd7-bdfd-4b42-b7a0-e57893d45967_terseLabel_en-US" xlink:label="lab_dei_AuditorFirmId" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Firm ID </link:label>
<link:label id="lab_dei_AuditorFirmId_label_en-US" xlink:label="lab_dei_AuditorFirmId" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Auditor Firm ID </link:label>
<link:loc xlink:type="locator" xlink:label="loc_dei_AuditorFirmId" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorFirmId"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorFirmId" xlink:to="lab_dei_AuditorFirmId" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A5.00SeniorNotesDueSeptember2020Member_01926160-02dc-43b4-bb41-969005f132b9_terseLabel_en-US" xlink:label="lab_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 5.00% Senior Notes due September 2020 </link:label>
<link:label id="lab_aon_A5.00SeniorNotesDueSeptember2020Member_label_en-US" xlink:label="lab_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 5.00% Senior Notes Due September 2020 [Member] </link:label>
<link:label id="lab_aon_A5.00SeniorNotesDueSeptember2020Member_documentation_en-US" xlink:label="lab_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> This element represents the senior notes that bear an interest rate of 5.00 percent and will mature in 2020. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:href="aon-20211231.xsd#aon_A5.00SeniorNotesDueSeptember2020Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:to="lab_aon_A5.00SeniorNotesDueSeptember2020Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_772f70a9-ba69-4a34-9bdf-eefb73c763bf_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash provided by (used for) investing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_7678e690-7c59-4f52-a48b-b47eed19b7af_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash used for investing activities </link:label>
<link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net Cash Provided by (Used in) Investing Activities </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_1ee1a9df-731c-423e-9c9e-9de5eab7458e_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change in projected benefit obligation </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:to="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_45e50082-5712-457f-ba14-6a61a3cdf237_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Change in assets and liabilities: </link:label>
<link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) in Operating Capital [Abstract] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_388f6ca0-bfc5-43b2-a1b3-18045cfac8be_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Vested (in dollars per share) </link:label>
<link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
<link:label id="lab_aon_A220SeniorNotesDueNovember2022Member_65f8a240-83c1-42be-bae2-3717bb566372_terseLabel_en-US" xlink:label="lab_aon_A220SeniorNotesDueNovember2022Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.20% Senior Notes due November 2022 </link:label>
<link:label id="lab_aon_A220SeniorNotesDueNovember2022Member_label_en-US" xlink:label="lab_aon_A220SeniorNotesDueNovember2022Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.20% Senior Notes due November 2022 [Member] </link:label>
<link:label id="lab_aon_A220SeniorNotesDueNovember2022Member_documentation_en-US" xlink:label="lab_aon_A220SeniorNotesDueNovember2022Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> 2.20% Senior Notes due November 2022 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_A220SeniorNotesDueNovember2022Member" xlink:href="aon-20211231.xsd#aon_A220SeniorNotesDueNovember2022Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_A220SeniorNotesDueNovember2022Member" xlink:to="lab_aon_A220SeniorNotesDueNovember2022Member" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EuropeMiddleEastAndAfricaMember_fa3c5fff-235c-4af9-b06f-a90527f0f330_terseLabel_en-US" xlink:label="lab_aon_EuropeMiddleEastAndAfricaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Europe, Middle East, & Africa other than U.K. and Ireland </link:label>
<link:label id="lab_aon_EuropeMiddleEastAndAfricaMember_label_en-US" xlink:label="lab_aon_EuropeMiddleEastAndAfricaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Europe, Middle East, And Africa [Member] </link:label>
<link:label id="lab_aon_EuropeMiddleEastAndAfricaMember_documentation_en-US" xlink:label="lab_aon_EuropeMiddleEastAndAfricaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Europe, Middle East, And Africa [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EuropeMiddleEastAndAfricaMember" xlink:href="aon-20211231.xsd#aon_EuropeMiddleEastAndAfricaMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EuropeMiddleEastAndAfricaMember" xlink:to="lab_aon_EuropeMiddleEastAndAfricaMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent_34236f60-4347-4cae-ae68-a92d864327d2_terseLabel_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred tax adjustments, including statutory rate changes </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent_label_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Deferred Tax Adjustments Including Statutory Rate Changes, Percent </link:label>
<link:label id="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent_documentation_en-US" xlink:label="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Effective Income Tax Rate Reconciliation, Deferred Tax Adjustments Including Statutory Rate Changes, Percent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:href="aon-20211231.xsd#aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:to="lab_aon_EffectiveIncomeTaxRateReconciliationDeferredTaxAdjustmentsIncludingStatutoryRateChangesPercent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ClassOfStockDomain_6c7b7a48-59f8-48e9-9e31-7d4bc276abfc_terseLabel_en-US" xlink:label="lab_us-gaap_ClassOfStockDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Class of Stock [Domain] </link:label>
<link:label id="lab_us-gaap_ClassOfStockDomain_label_en-US" xlink:label="lab_us-gaap_ClassOfStockDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Class of Stock [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfStockDomain" xlink:to="lab_us-gaap_ClassOfStockDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PaymentsToAcquireBusinessesGross_565460fd-9787-4651-930b-84605e3d7bca_verboseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesGross" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to acquire business </link:label>
<link:label id="lab_us-gaap_PaymentsToAcquireBusinessesGross_cace510e-2d20-479b-be3b-202703766679_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash </link:label>
<link:label id="lab_us-gaap_PaymentsToAcquireBusinessesGross_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Payments to Acquire Businesses, Gross </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBusinessesGross" xlink:to="lab_us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_e38a0ef9-150d-4c65-9e29-ba0912e239a9_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of credit facility, maximum borrowing capacity </link:label>
<link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility, Maximum Borrowing Capacity </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_8baf7db7-6842-4e46-8a55-74047209af8e_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Foreign currency translation and other </link:label>
<link:label id="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Goodwill, Foreign Currency Translation Gain (Loss) </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:to="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxAssetsAccruedInterest_2e01102f-2197-4c9b-b69a-50fb355a7dd0_terseLabel_en-US" xlink:label="lab_aon_DeferredTaxAssetsAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accrued interest </link:label>
<link:label id="lab_aon_DeferredTaxAssetsAccruedInterest_label_en-US" xlink:label="lab_aon_DeferredTaxAssetsAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Accrued Interest </link:label>
<link:label id="lab_aon_DeferredTaxAssetsAccruedInterest_documentation_en-US" xlink:label="lab_aon_DeferredTaxAssetsAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Assets, Accrued Interest </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxAssetsAccruedInterest" xlink:href="aon-20211231.xsd#aon_DeferredTaxAssetsAccruedInterest"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxAssetsAccruedInterest" xlink:to="lab_aon_DeferredTaxAssetsAccruedInterest" xlink:type="arc" order="1"/>
<link:label id="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock_31bb7ae0-5e37-41fd-8cb4-5b95718b9298_terseLabel_en-US" xlink:label="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Income Taxes (Assets and Liabilities Netted by Jurisdiction) as Classified in the Consolidated Statements of Financial Position </link:label>
<link:label id="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock_label_en-US" xlink:label="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Deferred Tax Assets and Liabilities Netted by Jurisdiction [Table Text Block] </link:label>
<link:label id="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock_documentation_en-US" xlink:label="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Disclosure of deferred income taxes (assets and liabilities netted by jurisdiction) as classified in the consolidated statements of financial position. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:href="aon-20211231.xsd#aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:to="lab_aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_f2f93761-444a-46d3-810d-07a98fde928a_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Discount rate </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_7efcf383-a626-4f5b-ab16-782ddf5cc54f_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Weighted-average discount rate used to determine net periodic benefit costs </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_d10bb261-e434-440c-bb17-3a0cbef7288d_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility [Line Items] </link:label>
<link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Line of Credit Facility [Line Items] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems" xlink:to="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member_ce081d8c-2351-4619-b5e6-03680e11dbbb_terseLabel_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees of Aon plc’s 3.50% Senior Notes due 2024 </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member_label_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 3.500 Senior Notes Due 2024 [Member] </link:label>
<link:label id="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member_documentation_en-US" xlink:label="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Guarantees Of Aon Plcs 3.500 Senior Notes Due 2024 </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:href="aon-20211231.xsd#aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:to="lab_aon_GuaranteesOfAonPlcs3500SeniorNotesDue2024Member" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DebtInstrumentNameDomain_1806cb47-dccc-4183-9309-8666147c6704_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument, Name [Domain] </link:label>
<link:label id="lab_us-gaap_DebtInstrumentNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Debt Instrument, Name [Domain] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="lab_us-gaap_DebtInstrumentNameDomain" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_OtherAssetsCurrent_bba09665-7d73-4a7a-a179-cdc6786164f1_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other current assets </link:label>
<link:label id="lab_us-gaap_OtherAssetsCurrent_34922f4e-6a8a-4fc2-8567-e03a0adc336f_totalLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total </link:label>
<link:label id="lab_us-gaap_OtherAssetsCurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other Assets, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsCurrent" xlink:to="lab_us-gaap_OtherAssetsCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_8dbeeefb-9682-4806-9d56-30d0e08424c9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Rate of compensation increase </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_94e6cf13-2d66-4ceb-846d-a4ecdd8e3c98_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Net amount recognized </link:label>
<link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:to="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:type="arc" order="1"/>
<link:label id="lab_aon_GovernmentAndAgencyBondsMember_1bf47946-8423-4fce-b2d9-9cb610b9b965_terseLabel_en-US" xlink:label="lab_aon_GovernmentAndAgencyBondsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Government and agency bonds </link:label>
<link:label id="lab_aon_GovernmentAndAgencyBondsMember_label_en-US" xlink:label="lab_aon_GovernmentAndAgencyBondsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Government and Agency Bonds [Member] </link:label>
<link:label id="lab_aon_GovernmentAndAgencyBondsMember_documentation_en-US" xlink:label="lab_aon_GovernmentAndAgencyBondsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Represents fixed income investments in government and agency bonds. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_GovernmentAndAgencyBondsMember" xlink:href="aon-20211231.xsd#aon_GovernmentAndAgencyBondsMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_GovernmentAndAgencyBondsMember" xlink:to="lab_aon_GovernmentAndAgencyBondsMember" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeLiability_736cb9c4-cd61-4ec7-990b-c493f61d8151_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative liabilities </link:label>
<link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeLiability_label_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Derivative Liability, Fair Value, Gross Liability </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:to="lab_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_ba6ca1ab-e882-4354-b7a1-abefe32ae8ca_periodStartLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents and funds held on behalf of clients at beginning of year </link:label>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_4ce448eb-de55-4622-8e74-017d392b882f_periodEndLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash and cash equivalents and funds held on behalf of clients at end of year </link:label>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_e51689dc-ec83-4cdd-8d38-f0db3387bd3e_totalLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Total cash and cash equivalents and funds held on behalf of clients </link:label>
<link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="arc" order="1"/>
<link:label id="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses_90e8a4fa-00df-4aa2-b085-173f0a01f59e_negatedLabel_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Other accrued expenses </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses_label_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Deferred Tax Liabilities, Other Accrued Expenses </link:label>
<link:label id="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses_documentation_en-US" xlink:label="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> The cumulative amount of the estimated future tax effects attributable to other accrued expenses not otherwise specified in this taxonomy that were expensed for tax purposes but capitalized in conformity with generally accepted accounting principles. </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:href="aon-20211231.xsd#aon_DeferredTaxLiabilitiesOtherAccruedExpenses"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:to="lab_aon_DeferredTaxLiabilitiesOtherAccruedExpenses" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_NotionalAmountOfNonderivativeInstruments_52cc7ee5-66b3-470a-b71b-fa37e450e9d5_terseLabel_en-US" xlink:label="lab_us-gaap_NotionalAmountOfNonderivativeInstruments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Outstanding Euro-denominated commercial paper </link:label>
<link:label id="lab_us-gaap_NotionalAmountOfNonderivativeInstruments_label_en-US" xlink:label="lab_us-gaap_NotionalAmountOfNonderivativeInstruments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Notional Amount of Nonderivative Instruments </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotionalAmountOfNonderivativeInstruments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NotionalAmountOfNonderivativeInstruments"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NotionalAmountOfNonderivativeInstruments" xlink:to="lab_us-gaap_NotionalAmountOfNonderivativeInstruments" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccruedIncomeTaxesCurrent_b8badcaa-690e-480d-b3b7-bcd1dffc88b0_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedIncomeTaxesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Taxes payable </link:label>
<link:label id="lab_us-gaap_AccruedIncomeTaxesCurrent_label_en-US" xlink:label="lab_us-gaap_AccruedIncomeTaxesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accrued Income Taxes, Current </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedIncomeTaxesCurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedIncomeTaxesCurrent" xlink:to="lab_us-gaap_AccruedIncomeTaxesCurrent" xlink:type="arc" order="1"/>
<link:label id="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod_2f051e1d-7e23-4e64-b165-e4e8ec7186d1_terseLabel_en-US" xlink:label="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> PSA, vesting conditions period (in years) </link:label>
<link:label id="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod_label_en-US" xlink:label="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Vesting Conditions Period </link:label>
<link:label id="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod_documentation_en-US" xlink:label="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Share-based Compensation Arrangement by Share-based Payment Award, Vesting Conditions Period </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:href="aon-20211231.xsd#aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:to="lab_aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_544b4666-ed11-405d-8ba9-01a0b7fbc664_terseLabel_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension Plan </link:label>
<link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_label_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Pension Plan [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionPlansDefinedBenefitMember" xlink:to="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:type="arc" order="1"/>
<link:label id="lab_aon_NumberOfSolutionLines_b8a6f050-d3ab-4758-a565-0fd8442e2b37_terseLabel_en-US" xlink:label="lab_aon_NumberOfSolutionLines" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number of solution lines </link:label>
<link:label id="lab_aon_NumberOfSolutionLines_label_en-US" xlink:label="lab_aon_NumberOfSolutionLines" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number Of Solution Lines </link:label>
<link:label id="lab_aon_NumberOfSolutionLines_documentation_en-US" xlink:label="lab_aon_NumberOfSolutionLines" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Number Of Solution Lines </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_NumberOfSolutionLines" xlink:href="aon-20211231.xsd#aon_NumberOfSolutionLines"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_NumberOfSolutionLines" xlink:to="lab_aon_NumberOfSolutionLines" xlink:type="arc" order="1"/>
<link:label id="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent_ed7d8552-7196-4022-8345-27a0a12fbd64_terseLabel_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Changes in Non-current operating lease liabilities </link:label>
<link:label id="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent_label_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) In Operating Lease Liabilities, Noncurrent </link:label>
<link:label id="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent_documentation_en-US" xlink:label="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Increase (Decrease) In Operating Lease Liabilities, Noncurrent </link:label>
<link:loc xlink:type="locator" xlink:label="loc_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:href="aon-20211231.xsd#aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:to="lab_aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_88220fef-d5c1-4912-b2dc-7524602d107f_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Finite-Lived Intangible Assets [Table] </link:label>
<link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Schedule of Finite-Lived Intangible Assets [Table] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:type="arc" order="1"/>
<link:label id="lab_us-gaap_AccountingStandardsUpdate201613Member_label_en-US" xlink:label="lab_us-gaap_AccountingStandardsUpdate201613Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US"> Accounting Standards Update 2016-13 [Member] </link:label>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
<link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingStandardsUpdate201613Member" xlink:to="lab_us-gaap_AccountingStandardsUpdate201613Member" xlink:type="arc" order="1"/>
</link:labelLink>
</link:linkbase>

8 Subsequent Filings that Reference this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/16/24  Aon plc                           10-K       12/31/23  141:142M                                   Workiva Inc Wde… FA01/FA
 2/24/23  Aon plc                           424B5                  2:682K                                   Donnelley … Solutions/FA
 2/23/23  Aon plc                           424B5                  1:647K                                   Donnelley … Solutions/FA
 2/17/23  Aon plc                           10-K       12/31/22  135:18M                                    Workiva Inc Wde… FA01/FA
 9/08/22  Aon plc                           424B5                  2:698K                                   Donnelley … Solutions/FA
 9/07/22  Aon plc                           424B5                  1:657K                                   Donnelley … Solutions/FA
 2/25/22  Aon plc                           424B5                  2:689K                                   Donnelley … Solutions/FA
 2/23/22  Aon plc                           424B5                  1:650K                                   Donnelley … Solutions/FA

53 Previous Filings that this Filing References

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

12/02/21  Aon plc                           8-K:8,9    11/29/21   16:870K                                   Donnelley … Solutions/FA
10/29/21  Aon plc                           10-Q        9/30/21   91:9.8M                                   Workiva Inc Wde… FA01/FA
 9/30/21  Aon plc                           8-K:1,2,9   9/28/21   13:2.2M                                   Donnelley … Solutions/FA
 8/23/21  Aon plc                           8-K:8,9     8/23/21   16:899K                                   Donnelley … Solutions/FA
 7/30/21  Aon plc                           10-Q        6/30/21   91:9.8M                                   Workiva Inc Wde… FA01/FA
 7/26/21  Aon plc                           8-K:1,5,7,9 7/26/21   15:312K                                   Donnelley … Solutions/FA
 6/04/21  Aon plc                           8-K:5,9     6/02/21   12:810K                                   Donnelley … Solutions/FA
 4/30/21  Aon plc                           10-Q        3/31/21   90:8.4M                                   Workiva Inc Wde… FA01/FA
 2/19/21  Aon plc                           10-K       12/31/20  138:19M                                    Workiva Inc Wde… FA01/FA
10/30/20  Aon plc                           8-K:1,5,9  10/27/20   13:263K                                   Donnelley … Solutions/FA
 6/25/20  Aon plc                           8-K:5,9     6/19/20   13:313K                                   Donnelley … Solutions/FA
 5/15/20  Aon plc                           8-K:8,9     5/12/20   16:749K                                   Donnelley … Solutions/FA
 5/01/20  Aon plc                           10-Q        3/31/20  107:18M                                    Workiva Inc Wde… FA01/FA
 4/02/20  Aon plc                           8-K:1,9     4/02/20   12:285K                                   Donnelley … Solutions/FA
 4/01/20  Aon plc                           8-K12B:1,2, 4/01/20   24:3.6M                                   Donnelley … Solutions/FA
 3/10/20  Aon plc                           8-K:1,9     3/09/20   14:1.1M                                   Donnelley … Solutions/FA
 2/14/20  Aon plc                           10-K       12/31/19  156:36M                                    Workiva Inc Wde… FA01/FA
11/15/19  Aon plc                           8-K:8,9    11/13/19   14:476K                                   Donnelley … Solutions/FA
 7/26/19  Aon plc                           10-Q        6/30/19  114:21M                                    Workiva Inc Wde… FA01/FA
 6/25/19  Aon plc                           8-K:5,9     6/21/19    3:69K                                    Donnelley … Solutions/FA
 5/02/19  Aon plc                           8-K:8,9     4/30/19    5:297K                                   Donnelley … Solutions/FA
 4/26/19  Aon plc                           10-Q        3/31/19  112:16M                                    Workiva Inc Wde… FA01/FA
12/03/18  Aon plc                           8-K:8,9    12/03/18    6:784K                                   Donnelley … Solutions/FA
 6/27/18  Aon plc                           8-K:5,9     6/21/18    3:63K                                    Donnelley … Solutions/FA
 5/15/18  Aon plc                           8-K:5,9     5/10/18    4:52K                                    Donnelley … Solutions/FA
 4/25/18  Aon plc                           8-K:5,9     4/19/18    3:36K                                    Donnelley … Solutions/FA
 2/20/18  Aon plc                           10-K       12/31/17  149:29M                                    Workiva Inc Wde… FA01/FA
10/20/17  Aon plc                           8-K:1,2,9  10/19/17    2:984K                                   Toppan Merrill/FA
 8/04/17  Aon plc                           10-Q        6/30/17   98:18M                                    Workiva Inc Wde… FA01/FA
 5/09/17  Aon plc                           10-Q        3/31/17   97:14M                                    Workiva Inc Wde… FA01/FA
 2/23/17  Aon plc                           10-K       12/31/16  150:28M                                    Workiva Inc Wde… FA01/FA
 2/10/17  Aon plc                           8-K:1,9     2/09/17    3:1.2M                                   Toppan Merrill/FA
10/28/16  Aon plc                           10-Q        9/30/16   89:16M                                    Workiva Inc Wde… FA01/FA
 7/29/16  Aon plc                           10-Q        6/30/16   91:16M                                    Workiva Inc Wde… FA01/FA
 4/29/16  Aon plc                           10-Q        3/31/16   96:13M                                    Workiva Inc Wde… FA01/FA
 2/29/16  Aon plc                           8-K:8,9     2/23/16    5:374K                                   Toppan Merrill/FA
 5/20/15  Aon plc                           8-K:8,9     5/13/15    6:983K                                   Toppan Merrill/FA
 2/26/15  Aon plc                           8-K:5,9     2/20/15    4:305K                                   Toppan Merrill/FA
 1/23/15  Aon plc                           8-K:5,9     1/16/15    2:142K                                   Toppan Merrill/FA
 5/27/14  Aon plc                           8-K:8,9     5/20/14    6:495K                                   Toppan Merrill/FA
11/26/13  Aon plc                           8-K:8,9    11/21/13    5:403K                                   Toppan Merrill/FA
 5/24/13  Aon plc                           8-K:8,9     5/21/13    6:944K                                   Toppan Merrill/FA
 3/29/13  Aon plc                           S-4                   11:1.9M                                   Toppan Merrill/FA
 4/02/12  Aon plc                           8-K12B:1,2, 3/29/12   22:6.4M                                   Toppan Merrill/FA
 3/30/12  Aon plc                           8-K:5,9     3/27/12    5:414K                                   Toppan Merrill/FA
 3/08/11  Aon plc                           8-K:1,2,9   3/08/11    2:572K                                   Toppan Merrill/FA
 9/10/10  Aon plc                           8-K:8,9     9/07/10   10:1.2M                                   Toppan Merrill/FA
 8/06/10  Aon plc                           10-Q        6/30/10   83:18M                                    Toppan Merrill/FA
11/17/09  Aon plc                           8-K:5,9    11/13/09    4:362K                                   Toppan Merrill/FA
10/03/07  Aon plc                           8-K:5,9    10/03/07    3:121K                                   Toppan Merrill/FA
 3/01/07  Aon plc                           10-K       12/31/06   13:2.3M                                   Toppan Merrill-FA
 5/24/06  Aon plc                           8-K:1,9     5/18/06    3:99K                                    Toppan Merrill/FA
 8/11/00  Aon plc                           10-Q        6/30/00    5:84K                                    Swift John S Co. Inc./FA
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