SEC Info℠  
    Home      Search      My Interests      Help      Sign In      Please Sign In

Syneos Health, Inc. – ‘10-K’ for 12/31/22 – ‘EX-101.SCH’

On:  Wednesday, 2/15/23, at 5:36pm ET   ·   As of:  2/16/23   ·   For:  12/31/22   ·   Accession #:  950170-23-2928   ·   File #:  1-36730

Previous ‘10-K’:  ‘10-K’ on 2/17/22 for 12/31/21   ·   Next & Latest:  ‘10-K/A’ on 5/1/23 for 12/31/22   ·   34 References:   

Find Words in Filings emoji
 		  in    Show  and   ↓Hints

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

 2/16/23  Syneos Health, Inc.               10-K       12/31/22  136:28M                                    Donnelley … Solutions/FA

Annual Report   —   Form 10-K

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   6.13M 
 2: EX-4        Ex-4.9                                              HTML     53K 
 4: EX-10       Ex-10.11.12                                         HTML    292K 
 5: EX-10       Ex-10.11.13                                         HTML    377K 
 6: EX-10       Ex-10.11.14                                         HTML    359K 
 7: EX-10       Ex-10.11.15                                         HTML    275K 
 8: EX-10       Ex-10.11.16                                         HTML    392K 
 9: EX-10       Ex-10.11.17                                         HTML    433K 
 3: EX-10       Ex-10.7                                             HTML    275K 
10: EX-21       Ex-21.1                                             HTML    268K 
11: EX-23       Ex-23.1                                             HTML     35K 
12: EX-31       Ex-31.1                                             HTML     39K 
13: EX-31       Ex-31.2                                             HTML     39K 
14: EX-32       Ex-32.1                                             HTML     38K 
15: EX-32       Ex-32.2                                             HTML     38K 
21: R1          Cover Page                                          HTML    105K 
22: R2          Consolidated Statements of Income                   HTML    116K 
23: R3          Consolidated Statements of Comprehensive Income     HTML     57K 
24: R4          Consolidated Statements of Comprehensive Income     HTML     41K 
                (Parenthetical)                                                  
25: R5          Consolidated Balance Sheets                         HTML    143K 
26: R6          Consolidated Balance Sheets (Parenthetical)         HTML     53K 
27: R7          Consolidated Statements of Cash Flows               HTML    141K 
28: R8          Consolidated Statements of Shareholders' Equity     HTML     86K 
29: R9          Basis of Presentation and Summary of Significant    HTML    171K 
                Accounting Policies                                              
30: R10         Financial Statement Details                         HTML    567K 
31: R11         Acquisitions, Divestitures, and Investments         HTML    146K 
32: R12         Long-Term Debt Obligations                          HTML    175K 
33: R13         Leases                                              HTML    243K 
34: R14         Derivatives                                         HTML     79K 
35: R15         Fair Value Measurements                             HTML    284K 
36: R16         Restructuring and Other Costs                       HTML     92K 
37: R17         Shareholders' Equity                                HTML    211K 
38: R18         Earnings Per Share                                  HTML     98K 
39: R19         Income Taxes                                        HTML    436K 
40: R20         Revenue from Contracts with Customers               HTML     47K 
41: R21         Segment Information                                 HTML    170K 
42: R22         Operations by Geographic Location                   HTML    109K 
43: R23         Concentration of Credit Risk                        HTML     42K 
44: R24         Related-Party Transactions                          HTML     50K 
45: R25         Commitments and Contingencies                       HTML     49K 
46: R26         Share-Based Compensation                            HTML    238K 
47: R27         Employee Benefit Plans                              HTML     62K 
48: R28         Basis of Presentation and Summary of Significant    HTML    232K 
                Accounting Policies (Policies)                                   
49: R29         Basis of Presentation and Summary of Significant    HTML     86K 
                Accounting Policies (Tables)                                     
50: R30         Financial Statement Details (Tables)                HTML    593K 
51: R31         Acquisitions, Divestitures, and Investments         HTML    118K 
                (Tables)                                                         
52: R32         Long-Term Debt Obligations (Tables)                 HTML    143K 
53: R33         Leases (Tables)                                     HTML    246K 
54: R34         Derivatives (Tables)                                HTML     71K 
55: R35         Fair Value Measurements (Tables)                    HTML    281K 
56: R36         Restructuring and Other Costs (Tables)              HTML     89K 
57: R37         Shareholders' Equity (Tables)                       HTML    199K 
58: R38         Earnings Per Share (Tables)                         HTML     94K 
59: R39         Income Taxes (Tables)                               HTML    420K 
60: R40         Segment Information (Tables)                        HTML    163K 
61: R41         Operations by Geographic Location (Tables)          HTML    112K 
62: R42         Share-Based Compensation (Tables)                   HTML    214K 
63: R43         Employee Benefit Plans (Tables)                     HTML     50K 
64: R44         Basis of Presentation and Summary of Significant    HTML    124K 
                Accounting Policies - Narrative (Details)                        
65: R45         Basis of Presentation and Summary of Significant    HTML     41K 
                Accounting Policies - Net Cash Pool Position                     
                (Details)                                                        
66: R46         Basis of Presentation and Summary of Significant    HTML     57K 
                Accounting Policies - Estimated Useful Lives of                  
                Property and Equipment (Details)                                 
67: R47         Basis of Presentation and Summary of Significant    HTML     49K 
                Accounting Policies - Estimated Useful Lives of                  
                Intangible Assets (Details)                                      
68: R48         Financial Statement Details - Accounts Receivable   HTML     59K 
                and Unbilled Services, net (Details)                             
69: R49         Financial Statement Details - Narrative (Details)   HTML     50K 
70: R50         Financial Statement Details - Schedule of Property  HTML     59K 
                and Equipment, Net (Details)                                     
71: R51         Financial Statement Details - Schedule of Goodwill  HTML     61K 
                (Details)                                                        
72: R52         Financial Statement Details - Schedule of           HTML     57K 
                Intangible Assets (Details)                                      
73: R53         Financial Statement Details - Schedule of Future    HTML     52K 
                Amortization Expense (Details)                                   
74: R54         Financial Statement Details - Schedule of Accrued   HTML     56K 
                Expenses (Details)                                               
75: R55         Financial Statement Details - Accumulated Other     HTML     54K 
                Comprehensive Loss, Net of Taxes (Details)                       
76: R56         Financial Statement Details - Tax Effects           HTML     61K 
                Allocated to Each Component of Other Comprehensive               
                (Loss) Income (Details)                                          
77: R57         Financial Statement Details - Schedule of Other     HTML     49K 
                (Income) Expense, Net (Details)                                  
78: R58         Financial Statement Details - Supplemental Cash     HTML     53K 
                Flow Information (Details)                                       
79: R59         Acquisitions, Divestitures, and Investments -       HTML    123K 
                Narrative (Details)                                              
80: R60         Acquisitions, Divestitures, and Investments -       HTML     52K 
                Preliminary Estimates of Fair Values of Intangible               
                Assets and Estimated Useful Lives (Details)                      
81: R61         Acquisitions, Divestitures, and Investments -       HTML     80K 
                Allocation of Consideration Transferred (Details)                
82: R62         Acquisitions, Divestitures, and Investments -       HTML     48K 
                Preliminary Estimates of Fair Value of Intangible                
                Assets and Estimated Useful Lives (Details)                      
83: R63         Long-Term Debt Obligations - Schedule of Debt       HTML     63K 
                Obligations (Details)                                            
84: R64         Long-Term Debt Obligations - Narrative (Details)    HTML    124K 
85: R65         Long-Term Debt Obligations - Schedule of Variable   HTML     63K 
                Rate Margins (Details)                                           
86: R66         Long-Term Debt Obligations - Accounts Receivable    HTML     66K 
                Financing Agreement (Details)                                    
87: R67         Long-Term Debt Obligations - Contractual            HTML     78K 
                Maturities of Debt Obligations (Details)                         
88: R68         Leases - Narrative (Details)                        HTML     40K 
89: R69         Leases - Components of Lease Cost (Details)         HTML     52K 
90: R70         Leases - Supplemental Balance Sheet Information     HTML     49K 
                Related to Leases (Details)                                      
91: R71         Leases - Supplemental Cash Flow Information         HTML     49K 
                Related to Leases (Details)                                      
92: R72         Leases - Supplemental Cash Flow Information,        HTML     45K 
                Weighted Average (Details)                                       
93: R73         Leases - Maturities of Lease Liabilities (Details)  HTML     92K 
94: R74         Derivatives - Narrative (Details)                   HTML     48K 
95: R75         Derivatives - Interest Rate Swaps Designated as     HTML     64K 
                Hedging Instruments on Consolidated Balance Sheets               
                (Details)                                                        
96: R76         Fair Value Measurements - Schedule of Assets and    HTML     78K 
                Liabilities Measured at Fair Value on a Recurring                
                Basis (Details)                                                  
97: R77         Fair Value Measurements - Schedule of Assets and    HTML     45K 
                Liabilities Measured at Fair Value on a Recurring                
                Basis (Parenthetical) (Details)                                  
98: R78         Fair Value Measurements - Reconciliation of         HTML     48K 
                Changes in the Carrying Amount of Contingent                     
                Consideration (Details)                                          
99: R79         Fair Value Measurements - Narrative (Details)       HTML     44K 
100: R80         Fair Value Measurements - Schedule of Estimated     HTML     60K  
                Fair Value (Details)                                             
101: R81         Restructuring and Other Costs - Schedule of         HTML     46K  
                Restructuring and other costs (Details)                          
102: R82         Restructuring and Other Costs - Liabilities         HTML     62K  
                Associated with Restructuring and Other Costs                    
                (Details)                                                        
103: R83         Shareholders' Equity - Shares of Common Stock       HTML     44K  
                Outstanding (Details)                                            
104: R84         Shareholders' Equity - Narrative (Details)          HTML     87K  
105: R85         Shareholders' Equity - Repurchase Activity          HTML     46K  
                (Details)                                                        
106: R86         Shareholders' Equity - Schedule of Stock by Class   HTML     59K  
                (Details)                                                        
107: R87         Earnings Per Share - Schedule of Earnings Per       HTML     75K  
                Share, Basic and Diluted (Details)                               
108: R88         Earnings Per Share - Narrative (Details)            HTML     38K  
109: R89         Income Taxes - Schedule of Components of Income     HTML     46K  
                before Provision for Income Taxes (Details)                      
110: R90         Income Taxes - Schedule of Components of Income     HTML     60K  
                Tax Expense (Benefit) (Details)                                  
111: R91         Income Taxes - Narrative (Details)                  HTML     79K  
112: R92         Income Taxes - Schedule of Effective Income Tax     HTML     83K  
                Rate Reconciliation (Details)                                    
113: R93         Income Taxes - Schedule of Effective Income Tax     HTML     43K  
                Rate Reconciliation (Parenthetical) (Details)                    
114: R94         Income Taxes - Summary of Valuation Allowance       HTML     53K  
                (Details)                                                        
115: R95         Income Taxes - Schedule of Deferred Tax Assets and  HTML     83K  
                Liabilities (Details)                                            
116: R96         Income Taxes - Schedule of Unrecognized Tax         HTML     54K  
                Benefits (Details)                                               
117: R97         Revenue from Contracts with Customers - Narrative   HTML     48K  
                (Details)                                                        
118: R98         Segment Information (Details)                       HTML     75K  
119: R99         Segment Information - Narrative (Details)           HTML     37K  
120: R100        Operations by Geographic Location - Total Revenue   HTML     64K  
                by Geographic Area (Details)                                     
121: R101        Operations by Geographic Location - Long-Lived      HTML     52K  
                Assets by Geographic Area (Details)                              
122: R102        Concentration of Credit Risk - Narrative (Details)  HTML     45K  
123: R103        Related-Party Transactions - Narrative (Details)    HTML     62K  
124: R104        Commitments and Contingencies - Narrative           HTML     52K  
                (Details)                                                        
125: R105        Share-Based Compensation - Narrative (Details)      HTML    101K  
126: R106        Share-Based Compensation - Stock Option Valuation   HTML     49K  
                Assumptions (Details)                                            
127: R107        Share-Based Compensation - Summary of Option        HTML     87K  
                Activity (Details)                                               
128: R108        Share-Based Compensation - Summary of Restricted    HTML     77K  
                Stock Unit Activity (Details)                                    
129: R109        Share-Based Compensation - Summary of Share-Based   HTML     43K  
                Compensation Expense (Details)                                   
130: R110        Employee Benefit Plans - Schedule of Contributions  HTML     38K  
                to Defined Contribution Plan (Details)                           
131: R111        Employee Benefit Plans - Narrative (Details)        HTML     50K  
134: XML         IDEA XML File -- Filing Summary                      XML    250K  
132: XML         XBRL Instance -- synh-20221231_htm                   XML   6.72M  
133: EXCEL       IDEA Workbook of Financial Reports                  XLSX    271K  
20: EX-101.CAL  XBRL Calculations -- synh-20221231_cal               XML    310K 
17: EX-101.DEF  XBRL Definitions -- synh-20221231_def                XML   1.22M 
18: EX-101.LAB  XBRL Labels -- synh-20221231_lab                     XML   2.35M 
16: EX-101.PRE  XBRL Presentations -- synh-20221231_pre              XML   1.89M 
19: EX-101.SCH  XBRL Schema -- synh-20221231                         XSD    298K 
135: JSON        XBRL Instance as JSON Data -- MetaLinks              752±  1.25M  
136: ZIP         XBRL Zipped Folder -- 0000950170-23-002928-xbrl      Zip   1.40M

‘EX-101.SCH’   —   XBRL Schema — synh-20221231

This Exhibit is an XBRL XML File.

                                                                                                                                                                                
<?xml version="1.0" encoding="windows-1252"?>
<!-- DFIN New ActiveDisclosure (SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2023-02-15T16:16:48.0530+00:00 -->
<!-- Copyright (c) 2023 Donnelly Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema targetNamespace="http://www.syneoshealth.com/20221231" attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:country="http://xbrl.sec.gov/country/2022" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:srt="http://fasb.org/srt/2022" xmlns:synh="http://www.syneoshealth.com/20221231" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:us-gaap="http://fasb.org/us-gaap/2022" xmlns:dei="http://xbrl.sec.gov/dei/2022" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink">
<xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance"/>
<xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase"/>
<xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt"/>
<xsd:import schemaLocation="https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd" namespace="http://xbrl.org/2020/extensible-enumerations-2.0"/>
<xsd:import schemaLocation="https://xbrl.sec.gov/dei/2022/dei-2022.xsd" namespace="http://xbrl.sec.gov/dei/2022"/>
<xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd" namespace="http://fasb.org/us-gaap/2022"/>
<xsd:import schemaLocation="https://xbrl.sec.gov/country/2022/country-2022.xsd" namespace="http://xbrl.sec.gov/country/2022"/>
<xsd:import schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd" namespace="http://www.xbrl.org/dtr/type/2020-01-21"/>
<xsd:import schemaLocation="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd" namespace="http://fasb.org/srt/2022"/>
<xsd:annotation>
<xsd:appinfo>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="synh-20221231_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Labels link" xlink:type="simple"/>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="synh-20221231_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation link" xlink:type="simple"/>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="synh-20221231_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition link" xlink:type="simple"/>
<link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="synh-20221231_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:title="Calculation link" xlink:type="simple"/>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DocumentCoverPage" id="Role_DocumentCoverPage">
<link:definition> 100000 - Document - Cover Page </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFINCOME" id="Role_StatementCONSOLIDATEDSTATEMENTSOFINCOME">
<link:definition> 100010 - Statement - CONSOLIDATED STATEMENTS OF INCOME </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/DisclosureLeasesMaturitiesOfLeaseLiabilitiesDetails2" id="DisclosureLeasesMaturitiesOfLeaseLiabilitiesDetails2">
<link:definition> 100020 - Disclosure - Leases - Maturities of Lease Liabilities (Details) 2 </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/DisclosureLongtermDebtObligationsContractualMaturitiesOfDebtObligationsDetails2" id="DisclosureLongtermDebtObligationsContractualMaturitiesOfDebtObligationsDetails2">
<link:definition> 100030 - Disclosure - Long-Term Debt Obligations - Contractual Maturities of Debt Obligations (Details) 2 </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/StatementConsolidatedBalanceSheets2" id="StatementConsolidatedBalanceSheets2">
<link:definition> 100040 - Statement - CONSOLIDATED BALANCE SHEETS 2 </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" id="Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME">
<link:definition> 100050 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEParenthetical" id="Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEParenthetical">
<link:definition> 100060 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETS" id="Role_StatementCONSOLIDATEDBALANCESHEETS">
<link:definition> 100070 - Statement - CONSOLIDATED BALANCE SHEETS </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETSParenthetical" id="Role_StatementCONSOLIDATEDBALANCESHEETSParenthetical">
<link:definition> 100080 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS" id="Role_StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS">
<link:definition> 100090 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" id="Role_StatementCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY">
<link:definition> 100100 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPolicies" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPolicies">
<link:definition> 100110 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetails" id="Role_DisclosureFinancialStatementDetails">
<link:definition> 100120 - Disclosure - Financial Statement Details </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestments" id="Role_DisclosureAcquisitionsDivestituresAndInvestments">
<link:definition> 100130 - Disclosure - Acquisitions, Divestitures, and Investments </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligations" id="Role_DisclosureLongTermDebtObligations">
<link:definition> 100140 - Disclosure - Long-Term Debt Obligations </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeases" id="Role_DisclosureLeases">
<link:definition> 100150 - Disclosure - Leases </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureDerivatives" id="Role_DisclosureDerivatives">
<link:definition> 100160 - Disclosure - Derivatives </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurements" id="Role_DisclosureFairValueMeasurements">
<link:definition> 100170 - Disclosure - Fair Value Measurements </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRestructuringAndOtherCosts" id="Role_DisclosureRestructuringAndOtherCosts">
<link:definition> 100180 - Disclosure - Restructuring and Other Costs </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquity" id="Role_DisclosureShareholdersEquity">
<link:definition> 100190 - Disclosure - Shareholders' Equity </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEarningsPerShare" id="Role_DisclosureEarningsPerShare">
<link:definition> 100200 - Disclosure - Earnings Per Share </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxes" id="Role_DisclosureIncomeTaxes">
<link:definition> 100210 - Disclosure - Income Taxes </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomers" id="Role_DisclosureRevenueFromContractsWithCustomers">
<link:definition> 100220 - Disclosure - Revenue from Contracts with Customers </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureSegmentInformation" id="Role_DisclosureSegmentInformation">
<link:definition> 100230 - Disclosure - Segment Information </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureOperationsByGeographicLocation" id="Role_DisclosureOperationsByGeographicLocation">
<link:definition> 100240 - Disclosure - Operations by Geographic Location </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureConcentrationOfCreditRisk" id="Role_DisclosureConcentrationOfCreditRisk">
<link:definition> 100250 - Disclosure - Concentration of Credit Risk </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRelatedPartyTransactions" id="Role_DisclosureRelatedPartyTransactions">
<link:definition> 100260 - Disclosure - Related-Party Transactions </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingencies" id="Role_DisclosureCommitmentsAndContingencies">
<link:definition> 100270 - Disclosure - Commitments and Contingencies </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensation" id="Role_DisclosureShareBasedCompensation">
<link:definition> 100280 - Disclosure - Share-Based Compensation </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEmployeeBenefitPlans" id="Role_DisclosureEmployeeBenefitPlans">
<link:definition> 100290 - Disclosure - Employee Benefit Plans </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesPolicies">
<link:definition> 100300 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesTables">
<link:definition> 100310 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsTables" id="Role_DisclosureFinancialStatementDetailsTables">
<link:definition> 100320 - Disclosure - Financial Statement Details (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestmentsTables" id="Role_DisclosureAcquisitionsDivestituresAndInvestmentsTables">
<link:definition> 100330 - Disclosure - Acquisitions, Divestitures, and Investments (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsTables" id="Role_DisclosureLongTermDebtObligationsTables">
<link:definition> 100340 - Disclosure - Long-Term Debt Obligations (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesTables" id="Role_DisclosureLeasesTables">
<link:definition> 100350 - Disclosure - Leases (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureDerivativesTables" id="Role_DisclosureDerivativesTables">
<link:definition> 100360 - Disclosure - Derivatives (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsTables" id="Role_DisclosureFairValueMeasurementsTables">
<link:definition> 100370 - Disclosure - Fair Value Measurements (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRestructuringAndOtherCostsTables" id="Role_DisclosureRestructuringAndOtherCostsTables">
<link:definition> 100380 - Disclosure - Restructuring and Other Costs (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquityTables" id="Role_DisclosureShareholdersEquityTables">
<link:definition> 100390 - Disclosure - Shareholders' Equity (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEarningsPerShareTables" id="Role_DisclosureEarningsPerShareTables">
<link:definition> 100400 - Disclosure - Earnings Per Share (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesTables" id="Role_DisclosureIncomeTaxesTables">
<link:definition> 100410 - Disclosure - Income Taxes (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureSegmentInformationTables" id="Role_DisclosureSegmentInformationTables">
<link:definition> 100420 - Disclosure - Segment Information (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureOperationsByGeographicLocationTables" id="Role_DisclosureOperationsByGeographicLocationTables">
<link:definition> 100430 - Disclosure - Operations by Geographic Location (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationTables" id="Role_DisclosureShareBasedCompensationTables">
<link:definition> 100440 - Disclosure - Share-Based Compensation (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEmployeeBenefitPlansTables" id="Role_DisclosureEmployeeBenefitPlansTables">
<link:definition> 100450 - Disclosure - Employee Benefit Plans (Tables) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails">
<link:definition> 100460 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNetCashPoolPositionDetails" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesNetCashPoolPositionDetails">
<link:definition> 100470 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Net Cash Pool Position (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesEstimatedUsefulLivesOfPropertyAndEquipmentDetails" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesEstimatedUsefulLivesOfPropertyAndEquipmentDetails">
<link:definition> 100480 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesEstimatedUsefulLivesOfIntangibleAssetsDetails" id="Role_DisclosureBasisOfPresentationAndSummaryOfSignificantAccountingPoliciesEstimatedUsefulLivesOfIntangibleAssetsDetails">
<link:definition> 100490 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Intangible Assets (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsAccountsReceivableAndUnbilledServicesNetDetails" id="Role_DisclosureFinancialStatementDetailsAccountsReceivableAndUnbilledServicesNetDetails">
<link:definition> 100500 - Disclosure - Financial Statement Details - Accounts Receivable and Unbilled Services, net (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsNarrativeDetails" id="Role_DisclosureFinancialStatementDetailsNarrativeDetails">
<link:definition> 100510 - Disclosure - Financial Statement Details - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfPropertyAndEquipmentNetDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfPropertyAndEquipmentNetDetails">
<link:definition> 100520 - Disclosure - Financial Statement Details - Schedule of Property and Equipment, Net (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfGoodwillDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfGoodwillDetails">
<link:definition> 100530 - Disclosure - Financial Statement Details - Schedule of Goodwill (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfIntangibleAssetsDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfIntangibleAssetsDetails">
<link:definition> 100540 - Disclosure - Financial Statement Details - Schedule of Intangible Assets (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfFutureAmortizationExpenseDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfFutureAmortizationExpenseDetails">
<link:definition> 100550 - Disclosure - Financial Statement Details - Schedule of Future Amortization Expense (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfAccruedExpensesDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfAccruedExpensesDetails">
<link:definition> 100560 - Disclosure - Financial Statement Details - Schedule of Accrued Expenses (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsAccumulatedOtherComprehensiveLossNetOfTaxesDetails" id="Role_DisclosureFinancialStatementDetailsAccumulatedOtherComprehensiveLossNetOfTaxesDetails">
<link:definition> 100570 - Disclosure - Financial Statement Details - Accumulated Other Comprehensive Loss, Net of Taxes (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsTaxEffectsAllocatedToEachComponentOfOtherComprehensiveLossIncomeDetails" id="Role_DisclosureFinancialStatementDetailsTaxEffectsAllocatedToEachComponentOfOtherComprehensiveLossIncomeDetails">
<link:definition> 100580 - Disclosure - Financial Statement Details - Tax Effects Allocated to Each Component of Other Comprehensive (Loss) Income (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsScheduleOfOtherIncomeExpenseNetDetails" id="Role_DisclosureFinancialStatementDetailsScheduleOfOtherIncomeExpenseNetDetails">
<link:definition> 100590 - Disclosure - Financial Statement Details - Schedule of Other (Income) Expense, Net (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFinancialStatementDetailsSupplementalCashFlowInformationDetails" id="Role_DisclosureFinancialStatementDetailsSupplementalCashFlowInformationDetails">
<link:definition> 100600 - Disclosure - Financial Statement Details - Supplemental Cash Flow Information (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestmentsNarrativeDetails" id="Role_DisclosureAcquisitionsDivestituresAndInvestmentsNarrativeDetails">
<link:definition> 100610 - Disclosure - Acquisitions, Divestitures, and Investments - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestmentsPreliminaryEstimatesOfFairValuesOfIntangibleAssetsAndEstimatedUsefulLivesDetails" id="Role_DisclosureAcquisitionsDivestituresAndInvestmentsPreliminaryEstimatesOfFairValuesOfIntangibleAssetsAndEstimatedUsefulLivesDetails">
<link:definition> 100620 - Disclosure - Acquisitions, Divestitures, and Investments - Preliminary Estimates of Fair Values of Intangible Assets and Estimated Useful Lives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestmentsAllocationOfConsiderationTransferredDetails" id="Role_DisclosureAcquisitionsDivestituresAndInvestmentsAllocationOfConsiderationTransferredDetails">
<link:definition> 100630 - Disclosure - Acquisitions, Divestitures, and Investments - Allocation of Consideration Transferred (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureAcquisitionsDivestituresAndInvestmentsPreliminaryEstimatesOfFairValueOfIntangibleAssetsAndEstimatedUsefulLivesDetails" id="Role_DisclosureAcquisitionsDivestituresAndInvestmentsPreliminaryEstimatesOfFairValueOfIntangibleAssetsAndEstimatedUsefulLivesDetails">
<link:definition> 100640 - Disclosure - Acquisitions, Divestitures, and Investments - Preliminary Estimates of Fair Value of Intangible Assets and Estimated Useful Lives (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsScheduleOfDebtObligationsDetails" id="Role_DisclosureLongTermDebtObligationsScheduleOfDebtObligationsDetails">
<link:definition> 100650 - Disclosure - Long-Term Debt Obligations - Schedule of Debt Obligations (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsNarrativeDetails" id="Role_DisclosureLongTermDebtObligationsNarrativeDetails">
<link:definition> 100660 - Disclosure - Long-Term Debt Obligations - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsScheduleOfVariableRateMarginsDetails" id="Role_DisclosureLongTermDebtObligationsScheduleOfVariableRateMarginsDetails">
<link:definition> 100670 - Disclosure - Long-Term Debt Obligations - Schedule of Variable Rate Margins (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsAccountsReceivableFinancingAgreementDetails" id="Role_DisclosureLongTermDebtObligationsAccountsReceivableFinancingAgreementDetails">
<link:definition> 100680 - Disclosure - Long-Term Debt Obligations - Accounts Receivable Financing Agreement (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLongTermDebtObligationsContractualMaturitiesOfDebtObligationsDetails" id="Role_DisclosureLongTermDebtObligationsContractualMaturitiesOfDebtObligationsDetails">
<link:definition> 100690 - Disclosure - Long-Term Debt Obligations - Contractual Maturities of Debt Obligations (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesNarrativeDetails" id="Role_DisclosureLeasesNarrativeDetails">
<link:definition> 100700 - Disclosure - Leases - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesComponentsOfLeaseCostDetails" id="Role_DisclosureLeasesComponentsOfLeaseCostDetails">
<link:definition> 100710 - Disclosure - Leases - Components of Lease Cost (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesSupplementalBalanceSheetInformationRelatedToLeasesDetails" id="Role_DisclosureLeasesSupplementalBalanceSheetInformationRelatedToLeasesDetails">
<link:definition> 100720 - Disclosure - Leases - Supplemental Balance Sheet Information Related to Leases (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesSupplementalCashFlowInformationRelatedToLeasesDetails" id="Role_DisclosureLeasesSupplementalCashFlowInformationRelatedToLeasesDetails">
<link:definition> 100730 - Disclosure - Leases - Supplemental Cash Flow Information Related to Leases (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesSupplementalCashFlowInformationWeightedAverageDetails" id="Role_DisclosureLeasesSupplementalCashFlowInformationWeightedAverageDetails">
<link:definition> 100740 - Disclosure - Leases - Supplemental Cash Flow Information, Weighted Average (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureLeasesMaturitiesOfLeaseLiabilitiesDetails" id="Role_DisclosureLeasesMaturitiesOfLeaseLiabilitiesDetails">
<link:definition> 100750 - Disclosure - Leases - Maturities of Lease Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureDerivativesNarrativeDetails" id="Role_DisclosureDerivativesNarrativeDetails">
<link:definition> 100760 - Disclosure - Derivatives - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureDerivativesInterestRateSwapsDesignatedAsHedgingInstrumentsOnConsolidatedBalanceSheetsDetails" id="Role_DisclosureDerivativesInterestRateSwapsDesignatedAsHedgingInstrumentsOnConsolidatedBalanceSheetsDetails">
<link:definition> 100770 - Disclosure - Derivatives - Interest Rate Swaps Designated as Hedging Instruments on Consolidated Balance Sheets (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" id="Role_DisclosureFairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails">
<link:definition> 100780 - Disclosure - Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisParentheticalDetails" id="Role_DisclosureFairValueMeasurementsScheduleOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisParentheticalDetails">
<link:definition> 100790 - Disclosure - Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsReconciliationOfChangesInCarryingAmountOfContingentConsiderationDetails" id="Role_DisclosureFairValueMeasurementsReconciliationOfChangesInCarryingAmountOfContingentConsiderationDetails">
<link:definition> 100800 - Disclosure - Fair Value Measurements - Reconciliation of Changes in the Carrying Amount of Contingent Consideration (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsNarrativeDetails" id="Role_DisclosureFairValueMeasurementsNarrativeDetails">
<link:definition> 100810 - Disclosure - Fair Value Measurements - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsScheduleOfEstimatedFairValueDetails" id="Role_DisclosureFairValueMeasurementsScheduleOfEstimatedFairValueDetails">
<link:definition> 100820 - Disclosure - Fair Value Measurements - Schedule of Estimated Fair Value (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRestructuringAndOtherCostsScheduleOfRestructuringAndOtherCostsDetails" id="Role_DisclosureRestructuringAndOtherCostsScheduleOfRestructuringAndOtherCostsDetails">
<link:definition> 100830 - Disclosure - Restructuring and Other Costs - Schedule of Restructuring and other costs (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRestructuringAndOtherCostsLiabilitiesAssociatedWithRestructuringAndOtherCostsDetails" id="Role_DisclosureRestructuringAndOtherCostsLiabilitiesAssociatedWithRestructuringAndOtherCostsDetails">
<link:definition> 100840 - Disclosure - Restructuring and Other Costs - Liabilities Associated with Restructuring and Other Costs (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquitySharesOfCommonStockOutstandingDetails" id="Role_DisclosureShareholdersEquitySharesOfCommonStockOutstandingDetails">
<link:definition> 100850 - Disclosure - Shareholders' Equity - Shares of Common Stock Outstanding (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquityNarrativeDetails" id="Role_DisclosureShareholdersEquityNarrativeDetails">
<link:definition> 100860 - Disclosure - Shareholders' Equity - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquityRepurchaseActivityDetails" id="Role_DisclosureShareholdersEquityRepurchaseActivityDetails">
<link:definition> 100870 - Disclosure - Shareholders' Equity - Repurchase Activity (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareholdersEquityScheduleOfStockByClassDetails" id="Role_DisclosureShareholdersEquityScheduleOfStockByClassDetails">
<link:definition> 100880 - Disclosure - Shareholders' Equity - Schedule of Stock by Class (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEarningsPerShareScheduleOfEarningsPerShareBasicAndDilutedDetails" id="Role_DisclosureEarningsPerShareScheduleOfEarningsPerShareBasicAndDilutedDetails">
<link:definition> 100890 - Disclosure - Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEarningsPerShareNarrativeDetails" id="Role_DisclosureEarningsPerShareNarrativeDetails">
<link:definition> 100900 - Disclosure - Earnings Per Share - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/DisclosureIncomeTaxesScheduleOfComponentsOfIncomeBeforeProvisionForIncomeTaxesDetails" id="DisclosureIncomeTaxesScheduleOfComponentsOfIncomeBeforeProvisionForIncomeTaxesDetails">
<link:definition> 100910 - Disclosure - Income Taxes - Schedule of Components of Income before Provision for Income Taxes (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfComponentsOfIncomeTaxExpenseBenefitDetails" id="Role_DisclosureIncomeTaxesScheduleOfComponentsOfIncomeTaxExpenseBenefitDetails">
<link:definition> 100920 - Disclosure - Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesNarrativeDetails" id="Role_DisclosureIncomeTaxesNarrativeDetails">
<link:definition> 100930 - Disclosure - Income Taxes - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationDetails" id="Role_DisclosureIncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationDetails">
<link:definition> 100940 - Disclosure - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationParentheticalDetails" id="Role_DisclosureIncomeTaxesScheduleOfEffectiveIncomeTaxRateReconciliationParentheticalDetails">
<link:definition> 100950 - Disclosure - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Parenthetical) (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesSummaryOfValuationAllowanceDetails" id="Role_DisclosureIncomeTaxesSummaryOfValuationAllowanceDetails">
<link:definition> 100960 - Disclosure - Income Taxes - Summary of Valuation Allowance (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfDeferredTaxAssetsAndLiabilitiesDetails" id="Role_DisclosureIncomeTaxesScheduleOfDeferredTaxAssetsAndLiabilitiesDetails">
<link:definition> 100970 - Disclosure - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfUnrecognizedTaxBenefitsDetails" id="Role_DisclosureIncomeTaxesScheduleOfUnrecognizedTaxBenefitsDetails">
<link:definition> 100980 - Disclosure - Income Taxes - Schedule of Unrecognized Tax Benefits (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersNarrativeDetails" id="Role_DisclosureRevenueFromContractsWithCustomersNarrativeDetails">
<link:definition> 100990 - Disclosure - Revenue from Contracts with Customers - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureSegmentInformationDetails" id="Role_DisclosureSegmentInformationDetails">
<link:definition> 101000 - Disclosure - Segment Information (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/DisclosureSegmentInformationNarrativeDetails" id="DisclosureSegmentInformationNarrativeDetails">
<link:definition> 101010 - Disclosure - Segment Information - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureOperationsByGeographicLocationTotalRevenueByGeographicAreaDetails" id="Role_DisclosureOperationsByGeographicLocationTotalRevenueByGeographicAreaDetails">
<link:definition> 101020 - Disclosure - Operations by Geographic Location - Total Revenue by Geographic Area (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureOperationsByGeographicLocationLongLivedAssetsByGeographicAreaDetails" id="Role_DisclosureOperationsByGeographicLocationLongLivedAssetsByGeographicAreaDetails">
<link:definition> 101030 - Disclosure - Operations by Geographic Location - Long-Lived Assets by Geographic Area (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureConcentrationOfCreditRiskNarrativeDetails" id="Role_DisclosureConcentrationOfCreditRiskNarrativeDetails">
<link:definition> 101040 - Disclosure - Concentration of Credit Risk - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureRelatedPartyTransactionsNarrativeDetails" id="Role_DisclosureRelatedPartyTransactionsNarrativeDetails">
<link:definition> 101050 - Disclosure - Related-Party Transactions - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesNarrativeDetails" id="Role_DisclosureCommitmentsAndContingenciesNarrativeDetails">
<link:definition> 101060 - Disclosure - Commitments and Contingencies - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationNarrativeDetails" id="Role_DisclosureShareBasedCompensationNarrativeDetails">
<link:definition> 101070 - Disclosure - Share-Based Compensation - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationStockOptionValuationAssumptionsDetails" id="Role_DisclosureShareBasedCompensationStockOptionValuationAssumptionsDetails">
<link:definition> 101080 - Disclosure - Share-Based Compensation - Stock Option Valuation Assumptions (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfOptionActivityDetails" id="Role_DisclosureShareBasedCompensationSummaryOfOptionActivityDetails">
<link:definition> 101090 - Disclosure - Share-Based Compensation - Summary of Option Activity (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfRestrictedStockUnitActivityDetails" id="Role_DisclosureShareBasedCompensationSummaryOfRestrictedStockUnitActivityDetails">
<link:definition> 101100 - Disclosure - Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfShareBasedCompensationExpenseDetails" id="Role_DisclosureShareBasedCompensationSummaryOfShareBasedCompensationExpenseDetails">
<link:definition> 101110 - Disclosure - Share-Based Compensation - Summary of Share-Based Compensation Expense (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEmployeeBenefitPlansScheduleOfContributionsToDefinedContributionPlanDetails" id="Role_DisclosureEmployeeBenefitPlansScheduleOfContributionsToDefinedContributionPlanDetails">
<link:definition> 101120 - Disclosure - Employee Benefit Plans - Schedule of Contributions to Defined Contribution Plan (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
<link:roleType roleURI="http://www.syneoshealth.com/20221231/taxonomy/role/Role_DisclosureEmployeeBenefitPlansNarrativeDetails" id="Role_DisclosureEmployeeBenefitPlansNarrativeDetails">
<link:definition> 101130 - Disclosure - Employee Benefit Plans - Narrative (Details) </link:definition>
<link:usedOn> link:presentationLink </link:usedOn>
<link:usedOn> link:calculationLink </link:usedOn>
<link:usedOn> link:definitionLink </link:usedOn>
</link:roleType>
</xsd:appinfo>
</xsd:annotation>
<xsd:element id="synh_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualLifeAbstract" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualLifeAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SharesAuthorizedAbstract" name="SharesAuthorizedAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SharesIssuedAbstract" name="SharesIssuedAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SharesOutstandingAbstract" name="SharesOutstandingAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccruedRebatesToCustomersCurrent" name="AccruedRebatesToCustomersCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_AssetsExchangedInCash" name="AssetsExchangedInCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedExpenses" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContractWithCustomerLiability" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContractWithCustomerLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAccountsReceivableAndUnbilledServices" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAccountsReceivableAndUnbilledServices" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentTaxSharingObligation" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentTaxSharingObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_BusinessExitCostsAndGainLossOnTerminationOfLease" name="BusinessExitCostsAndGainLossOnTerminationOfLease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_BusinessExitOtherCosts" name="BusinessExitOtherCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_CashandCashEquivalentsCashPoolingAgreementCashPoolBorrowings" name="CashandCashEquivalentsCashPoolingAgreementCashPoolBorrowings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_CashandCashEquivalentsCashPoolingAgreementGrossCashPosition" name="CashandCashEquivalentsCashPoolingAgreementGrossCashPosition" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_CashandCashEquivalentsCashPoolingAgreementNetCashPosition" name="CashandCashEquivalentsCashPoolingAgreementNetCashPosition" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_ChangesInFairValueRecognizedInEarnings" name="ChangesInFairValueRecognizedInEarnings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ClassBCommonStockConversionRatio" name="ClassBCommonStockConversionRatio" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_CommonandPreferredStockSharesAuthorized" name="CommonandPreferredStockSharesAuthorized" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
<xsd:element id="synh_CommonStockVotes" name="CommonStockVotes" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ContractTerminationNoticePeriod" name="ContractTerminationNoticePeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ContractualObligationNotYetSatisfied" name="ContractualObligationNotYetSatisfied" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_DebtInstrumentCovenantFirstLienLeverageRatioMaximum" name="DebtInstrumentCovenantFirstLienLeverageRatioMaximum" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_DeferredCompensationArrangementWithIndividualCashAwardsGrantedCommissionsPercentage" name="DeferredCompensationArrangementWithIndividualCashAwardsGrantedCommissionsPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_DeferredTaxAssetInterestLimitationCarryforward" name="DeferredTaxAssetInterestLimitationCarryforward" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_DeferredTaxAssetsTaxDeferredExpenseLeaseObligations" name="DeferredTaxAssetsTaxDeferredExpenseLeaseObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_DeferredTaxAssetsTaxDeferredExpensePrepaidRoyalty" name="DeferredTaxAssetsTaxDeferredExpensePrepaidRoyalty" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_DeferredTaxLiabilitiesRightOfUseAssets" name="DeferredTaxLiabilitiesRightOfUseAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_EffectiveIncomeTaxRateReconciliationExecutiveCompensationLimitationAmount" name="EffectiveIncomeTaxRateReconciliationExecutiveCompensationLimitationAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_EffectiveIncomeTaxRateReconciliationForeignEarningsNotIndefinitelyReinvested" name="EffectiveIncomeTaxRateReconciliationForeignEarningsNotIndefinitelyReinvested" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_EffectiveIncomeTaxRateReconciliationForeignIncomeInclusion" name="EffectiveIncomeTaxRateReconciliationForeignIncomeInclusion" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_FairValueMeasurementsAssetsLevel1ToLevel2TransfersAmount" name="FairValueMeasurementsAssetsLevel1ToLevel2TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_FairValueMeasurementsAssetsLevel2ToLevel1TransfersAmount" name="FairValueMeasurementsAssetsLevel2ToLevel1TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_FairValueMeasurementsLiabilitiesLevel1ToLevel2TransfersAmount" name="FairValueMeasurementsLiabilitiesLevel1ToLevel2TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_FairValueMeasurementsLiabilitiesLevel2ToLevel1TransfersAmount" name="FairValueMeasurementsLiabilitiesLevel2ToLevel1TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_FinanceLeaseCosts" name="FinanceLeaseCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_FinanceLeaseLiabilityManagementFee" name="FinanceLeaseLiabilityManagementFee" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_FinanceLeaseRightOfUseAssetAccumulatedDepreciation" name="FinanceLeaseRightOfUseAssetAccumulatedDepreciation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_FinanceLeaseVariableLeaseCost" name="FinanceLeaseVariableLeaseCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_FixedLeaseCosts" name="FixedLeaseCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_ForeignDerivedIntangibleIncome" name="ForeignDerivedIntangibleIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ForeignEarningsPreviouslyTaxedintheUSIntendedToBePermanentlyReinvested" name="ForeignEarningsPreviouslyTaxedintheUSIntendedToBePermanentlyReinvested" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ForeignEarningsPreviouslyTaxedintheUSIntendedToBeRepatriated" name="ForeignEarningsPreviouslyTaxedintheUSIntendedToBeRepatriated" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ForeignEarningsPreviouslyTaxedintheUSTotal" name="ForeignEarningsPreviouslyTaxedintheUSTotal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_GuarantorObligationsPercentOfForeignSubsidiaryCapitalStockSecuringDebt" name="GuarantorObligationsPercentOfForeignSubsidiaryCapitalStockSecuringDebt" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_IncomeTaxReconciliationNondeductibleExpenseCapitalLossCarryforward" name="IncomeTaxReconciliationNondeductibleExpenseCapitalLossCarryforward" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_IncreaseDecreaseInAccountsReceivableContractWithCustomerAssetNetCurrentAndContractWithCustomerLiabilityCurrent" name="IncreaseDecreaseInAccountsReceivableContractWithCustomerAssetNetCurrentAndContractWithCustomerLiabilityCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LeaseRemainingLeaseTerm" name="LeaseRemainingLeaseTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_LesseeOperatingLeaseLiabilityManagementFee" name="LesseeOperatingLeaseLiabilityManagementFee" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestAfterYearFive" name="LongTermDebtInterestAfterYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestFairValue" name="LongTermDebtInterestFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestYearFive" name="LongTermDebtInterestYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestYearFour" name="LongTermDebtInterestYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestYearOne" name="LongTermDebtInterestYearOne" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestYearThree" name="LongTermDebtInterestYearThree" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LongTermDebtInterestYearTwo" name="LongTermDebtInterestYearTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_LossContingencyNumberOfActionsTakenByPlaintiff" name="LossContingencyNumberOfActionsTakenByPlaintiff" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_LossGainOnSaleOfBusinessIncomeTax" name="LossGainOnSaleOfBusinessIncomeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_NumberOfPrivateEquityFunds" name="NumberOfPrivateEquityFunds" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDue" name="OperatingAndFinanceLeaseLiabilityPaymentsDue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDueAfterYearFive" name="OperatingAndFinanceLeaseLiabilityPaymentsDueAfterYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDueYearFive" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDueYearFour" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDueYearThree" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearThree" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsDueYearTwo" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingAndFinanceLeaseLiabilityPaymentsNextTwelveMonths" name="OperatingAndFinanceLeaseLiabilityPaymentsNextTwelveMonths" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingLeaseLiabilityClosedOutInExchangeForRightOfUseAsset" name="OperatingLeaseLiabilityClosedOutInExchangeForRightOfUseAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OperatingLeaseVariableLeaseCost" name="OperatingLeaseVariableLeaseCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_OperatingLossCarryforwardsExpirationYear" name="OperatingLossCarryforwardsExpirationYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent1" name="OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent1" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_OtherSundryNonoperatingIncomeExpense" name="OtherSundryNonoperatingIncomeExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_PaymentOfLoansToUnconsolidatedAffiliates" name="PaymentOfLoansToUnconsolidatedAffiliates" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_PercentageOfOutstandingSharesPurchase" name="PercentageOfOutstandingSharesPurchase" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
<xsd:element id="synh_QuantitativeAnalysisReportingUnitPercentage" name="QuantitativeAnalysisReportingUnitPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_QuantitativeAnalysisReportingUnitValue" name="QuantitativeAnalysisReportingUnitValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_ReceivablesFinancingAgreementPrepaymentOfLoanFacilityNoticeTerm" name="ReceivablesFinancingAgreementPrepaymentOfLoanFacilityNoticeTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ReceivablesFinancingAgreementTerminationOrReductionToFacilityLimitNoticeTerm" name="ReceivablesFinancingAgreementTerminationOrReductionToFacilityLimitNoticeTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ReceivablesNetCurrentAndContractWithCustomerAssetNetCurrent" name="ReceivablesNetCurrentAndContractWithCustomerAssetNetCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_RelatedPartyTransactionNumberOfCounterparties" name="RelatedPartyTransactionNumberOfCounterparties" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_RepaymentOfCreditFacilityPercentage" name="RepaymentOfCreditFacilityPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
<xsd:element id="synh_RestructuringChargeIncludingOtherCosts" name="RestructuringChargeIncludingOtherCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_RestructuringChargeIncludingOtherCosts1" name="RestructuringChargeIncludingOtherCosts1" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_RevenueFromChangeInEstimate" name="RevenueFromChangeInEstimate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_RevenuePerformanceObligationContractTerm" name="RevenuePerformanceObligationContractTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlans" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlans" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_StockholdersEquityAttributableToParentAdjustedBalance" name="StockholdersEquityAttributableToParentAdjustedBalance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_StockRepurchaseProgramSharesPurchasedValue" name="StockRepurchaseProgramSharesPurchasedValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_TaxCutsAndJobsActOf2017BaseErosionAndAntiAbuseTax" name="TaxCutsAndJobsActOf2017BaseErosionAndAntiAbuseTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_TradeReceivablesSold" name="TradeReceivablesSold" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ValuationAllowanceAndReservesChargedToEquity" name="ValuationAllowanceAndReservesChargedToEquity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ValuationAllowancesAndReservesDeferredTaxAssetsAssumedThroughBusinessCombinations" name="ValuationAllowancesAndReservesDeferredTaxAssetsAssumedThroughBusinessCombinations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ValuationAllowancesAndReservesDeferredTaxAssetsReleasedThroughBusinessDispositions" name="ValuationAllowancesAndReservesDeferredTaxAssetsReleasedThroughBusinessDispositions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
<xsd:element id="synh_ValuationAllowancesandReservesForeignCurrencyExchange" name="ValuationAllowancesandReservesForeignCurrencyExchange" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_ValuationAllowancesAndReservesOtherAdjustments" name="ValuationAllowancesAndReservesOtherAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo1TermLoanADueAugust2022Member" name="A2017CreditAgreementAmendmentNo1TermLoanADueAugust2022Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2RevolvingCreditFacilityDueAugust2024Member" name="A2017CreditAgreementAmendmentNo2RevolvingCreditFacilityDueAugust2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermAFacilityDueNovember2027Member" name="A2017CreditAgreementAmendmentNo2TermAFacilityDueNovember2027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermLoanADueMarch2024FundedAmountMember" name="A2017CreditAgreementAmendmentNo2TermLoanADueMarch2024FundedAmountMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermLoanADueMarch2024Member" name="A2017CreditAgreementAmendmentNo2TermLoanADueMarch2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermLoanATrancheOneDueMarch2024Member" name="A2017CreditAgreementAmendmentNo2TermLoanATrancheOneDueMarch2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermLoanATrancheTwoDueAugust2024Member" name="A2017CreditAgreementAmendmentNo2TermLoanATrancheTwoDueAugust2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementAmendmentNo2TermLoanBDueAugust2024Member" name="A2017CreditAgreementAmendmentNo2TermLoanBDueAugust2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementRevolvingCreditFacilityDueAugust2022Member" name="A2017CreditAgreementRevolvingCreditFacilityDueAugust2022Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementTermBLoanMember" name="A2017CreditAgreementTermBLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_A2017CreditAgreementTermLoanBDueAugust2024Member" name="A2017CreditAgreementTermLoanBDueAugust2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableFinancingAgreementDueOctober2022Member" name="AccountsReceivableFinancingAgreementDueOctober2022Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableFinancingAgreementDueOctober2024Member" name="AccountsReceivableFinancingAgreementDueOctober2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableFinancingAgreementDueOctober2025Member" name="AccountsReceivableFinancingAgreementDueOctober2025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsreceivablefinancingagreementdueoctobertwothousandTwentyFiveMember" name="AccountsreceivablefinancingagreementdueoctobertwothousandTwentyFiveMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableFinancingAgreementDueSeptember2021Member" name="AccountsReceivableFinancingAgreementDueSeptember2021Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableSecuritizationMember" name="AccountsReceivableSecuritizationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AcquiredBacklogMember" name="AcquiredBacklogMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AcquiredTechnologyMember" name="AcquiredTechnologyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AmendedAndRestatedCreditAgreementMember" name="AmendedAndRestatedCreditAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AmendmentNo1TermBLoanMember" name="AmendmentNo1TermBLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AssetsNotYetPlacedInServiceMember" name="AssetsNotYetPlacedInServiceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_BermudezAndVaitkuvieneActionMember" name="BermudezAndVaitkuvieneActionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_ClinicalSolutionsSegmentMember" name="ClinicalSolutionsSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_CommercialSolutionsSegmentMember" name="CommercialSolutionsSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_ComputerEquipmentandSoftwareMember" name="ComputerEquipmentandSoftwareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_CostofServicesMember" name="CostofServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_CreditAgreementAmendmentNo5TermLoanAMember" name="CreditAgreementAmendmentNo5TermLoanAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_EmployeeSeveranceCostsIncludingExecutiveTransitionCostsMember" name="EmployeeSeveranceCostsIncludingExecutiveTransitionCostsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_EurocurrencyRateMember" name="EurocurrencyRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_FederalFundsRateMember" name="FederalFundsRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_HealthcareAndLifeSciencesIndustryMember" name="HealthcareAndLifeSciencesIndustryMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_IllingworthResearchMember" name="IllingworthResearchMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InApril2024AndJuly2024Member" name="InApril2024AndJuly2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_IncrementalTermLoanMember" name="IncrementalTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InOctober2024Member" name="InOctober2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InterestRateSwapExpiringJune302021Member" name="InterestRateSwapExpiringJune302021Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InterestRateSwapExpiringMarch312023Member" name="InterestRateSwapExpiringMarch312023Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InventivMember" name="InventivMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_InVentivMergerMember" name="InVentivMergerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_PatientCommunitiesMember" name="PatientCommunitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_PerformanceBasedRestrictedStockUnitsMember" name="PerformanceBasedRestrictedStockUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_RelatedPartyMember" name="RelatedPartyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_ResearchAndGeneralBusinessTaxCreditsMember" name="ResearchAndGeneralBusinessTaxCreditsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_RevolvingFacilityDueNovember2027Member" name="RevolvingFacilityDueNovember2027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_RxDataScienceAcquisitionsMember" name="RxDataScienceAcquisitionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_RxDataScienceMember" name="RxDataScienceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SeniorNoteDue2029Member" name="SeniorNoteDue2029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SeniorUnsecuredNotesDue2029Member" name="SeniorUnsecuredNotesDue2029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SeniorUnsecuredNotesDueJanuary2029Member" name="SeniorUnsecuredNotesDueJanuary2029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_StudyKikAcquisitionMember" name="StudyKikAcquisitionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_SynteractAcquisitionMember" name="SynteractAcquisitionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TermAFacilityDueNovember2027Member" name="TermAFacilityDueNovember2027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TermAFacilityMember" name="TermAFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TermLoanATrancheOneDueMarch2024Member" name="TermLoanATrancheOneDueMarch2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TermLoanATrancheTwoDueAugust2024Member" name="TermLoanATrancheTwoDueAugust2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TermLoanMember" name="TermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_ThreePointSixHundredTwentyFivePercentageSeniorNotesMember" name="ThreePointSixHundredTwentyFivePercentageSeniorNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_ThroughJanuary2024Member" name="ThroughJanuary2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TimeBasedRestrictedStockUnitsAwardsMember" name="TimeBasedRestrictedStockUnitsAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TwoThousandFourteenEquityIncentivePlanMember" name="TwoThousandFourteenEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TwoThousandTwentyOneStockRepurchaseProgramMember" name="TwoThousandTwentyOneStockRepurchaseProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_TwoThousandTwentyTwoStockRepurchaseProgramMember" name="TwoThousandTwentyTwoStockRepurchaseProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
<xsd:element id="synh_AccountsReceivableUnbilledServicesAndDeferredRevenuePoliciesTextBlock" name="AccountsReceivableUnbilledServicesAndDeferredRevenuePoliciesTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_AssetsAndLiabilitiesLesseeTableTextBlock" name="AssetsAndLiabilitiesLesseeTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_GeographicInformationTextBlock" name="GeographicInformationTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_LesseeSupplementalCashFlowInformationTableTextBlock" name="LesseeSupplementalCashFlowInformationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_LesseeSupplementalCashFlowInformationWeightedAverageTableTextBlock" name="LesseeSupplementalCashFlowInformationWeightedAverageTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_MacroeconomicEnvironmentPoliciesTextBlock" name="MacroeconomicEnvironmentPoliciesTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_PrincipalBusinessPoliciesTextBlock" name="PrincipalBusinessPoliciesTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ReimbursableExpensesPolicyPolicyTextBlock" name="ReimbursableExpensesPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ScheduleOfCashPoolPositionTableTextBlock" name="ScheduleOfCashPoolPositionTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
<xsd:element id="synh_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsEstimatedUsefulLifeTableTextBlock" name="ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsEstimatedUsefulLifeTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>

4 Subsequent Filings that Reference this Filing

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

 6/27/23  Syneos Health, Inc.               DEFM14A                1:2.4M                                   Donnelley … Solutions/FA
 6/27/23  Syneos Health, Inc.               PRER14A                2:2.5M                                   Donnelley … Solutions/FA
 6/15/23  Syneos Health, Inc.               PREM14A     6/14/23    2:2.3M                                   Donnelley … Solutions/FA
 5/10/23  Syneos Health, Inc.               10-Q        3/31/23   88:10M                                    Donnelley … Solutions/FA

30 Previous Filings that this Filing References

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

 1/09/23  Syneos Health, Inc.               8-K:2,5,9   1/05/23   13:295K                                   Donnelley … Solutions/FA
12/23/22  Syneos Health, Inc.               8-K:5,9    12/23/22   12:529K                                   ActiveDisclosure/FA
11/07/22  Syneos Health, Inc.               8-K:1,2,9  11/04/22   11:2.5M                                   ActiveDisclosure/FA
11/04/22  Syneos Health, Inc.               10-Q        9/30/22   87:14M                                    Donnelley … Solutions/FA
 8/02/22  Syneos Health, Inc.               10-Q        6/30/22   87:12M                                    Donnelley … Solutions/FA
 6/01/22  Syneos Health, Inc.               8-K:5,8,9   5/25/22   13:605K                                   ActiveDisclosure/FA
 4/29/22  Syneos Health, Inc.               8-K:5,9     4/28/22   14:887K                                   ActiveDisclosure/FA
 4/29/22  Syneos Health, Inc.               10-Q        3/31/22   85:9M                                     ActiveDisclosure/FA
 2/17/22  Syneos Health, Inc.               10-K       12/31/21  134:25M                                    ActiveDisclosure/FA
11/03/21  Syneos Health, Inc.               10-Q        9/30/21   88:13M                                    ActiveDisclosure/FA
 8/09/21  Syneos Health, Inc.               10-Q        6/30/21   86:11M                                    ActiveDisclosure/FA
 2/18/21  Syneos Health, Inc.               10-K       12/31/20  130:23M                                    ActiveDisclosure/FA
 1/21/21  Syneos Health, Inc.               8-K:5,9     1/14/21   12:948K                                   ActiveDisclosure/FA
11/25/20  Syneos Health, Inc.               8-K:1,2,8,911/24/20   14:2.7M                                   Donnelley … Solutions/FA
10/29/20  Syneos Health, Inc.               10-Q        9/30/20   88:13M                                    ActiveDisclosure/FA
 4/30/20  Syneos Health, Inc.               10-Q        3/31/20   83:7.6M
 2/20/20  Syneos Health, Inc.               10-K       12/31/19  137:20M
10/31/19  Syneos Health, Inc.               10-Q        9/30/19   94:14M
 8/06/19  Syneos Health, Inc.               10-Q        6/30/19   95:17M
 3/18/19  Syneos Health, Inc.               10-K       12/31/18  136:18M
11/06/18  Syneos Health, Inc.               10-Q        9/30/18   98:12M
 8/02/18  Syneos Health, Inc.               10-Q        6/30/18   94:14M
 6/29/18  Syneos Health, Inc.               8-K:1,2,9   6/29/18    3:934K                                   Donnelley … Solutions/FA
 5/25/18  Syneos Health, Inc.               8-K:5,9     5/24/18    3:217K                                   Donnelley … Solutions/FA
 5/09/18  Syneos Health, Inc.               10-Q        3/31/18   92:8.3M
 1/08/18  Syneos Health, Inc.               8-K:5,7,9   1/04/18    4:156K                                   Donnelley … Solutions/FA
 8/01/17  Syneos Health, Inc.               8-K:1,2,5,8 8/01/17    8:3.7M                                   Donnelley … Solutions/FA
 4/06/17  Syneos Health, Inc.               8-K:5,9     4/01/17    2:76K
 7/28/16  Syneos Health, Inc.               8-K:5,9     7/27/16    6:393K                                   Donnelley … Solutions/FA
10/27/14  Syneos Health, Inc.               S-1/A                  6:4.5M                                   Toppan Merrill-FA
↑Top
Filing Submission 0000950170-23-002928   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)
Copyright © 2024 Fran Finnegan & Company LLC – All Rights Reserved.
About — Privacy — Redactions — Help — Thu., May 16, 2:40:49.3am ET