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<link:definition>1013 - Disclosure - Credit Facility</link:definition>
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<link:definition>1015 - Disclosure - Long-Term Payroll Tax Liability</link:definition>
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<link:definition>1022 - Disclosure - Earnings per Share</link:definition>
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<link:definition>1024 - Disclosure - Fair Value Measurements</link:definition>
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<link:definition>1025 - Disclosure - Quarterly Financial Information</link:definition>
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<link:definition>1026 - Disclosure - Business Segments and Geographic Information</link:definition>
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<link:definition>1027 - Disclosure - SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS</link:definition>
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<link:definition>1028 - Disclosure - Summary of Significant Accounting Policies (Policies)</link:definition>
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<link:definition>1029 - Disclosure - Summary of Significant Accounting Policies (Tables)</link:definition>
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<link:definition>1030 - Disclosure - Revenue from Contracts with Customers (Tables)</link:definition>
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<link:definition>1031 - Disclosure - Business Combinations (Tables)</link:definition>
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<link:definition>1033 - Disclosure - Credit Facility (Tables)</link:definition>
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<link:definition>1041 - Disclosure - Quarterly Financial Information (Tables)</link:definition>
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<link:definition>1043 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)</link:definition>
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<link:definition>1045 - Disclosure - Revenue from Contracts with Customers - Additional Information (Detail)</link:definition>
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<link:definition>1046 - Disclosure - Revenue from Contracts with Customers - Summary of Disaggregation of Our Revenues by Contract Type and Operating Segment (Detail)</link:definition>
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<link:definition>1047 - Disclosure - Revenue from Contracts with Customers - Summary of Revenue from External Customers (Detail)</link:definition>
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<link:definition>1048 - Disclosure - Business Combinations - Additional Information (Detail)</link:definition>
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<link:definition>1049 - Disclosure - Business Combinations - Summary of Fair Value of Consideration for Acquired Business (Detail)</link:definition>
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<link:definition>1050 - Disclosure - Business Combinations - Summary of Fair Value of Consideration for Acquired Business (Parenthetical) (Detail)</link:definition>
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<link:definition>1051 - Disclosure - Business Combinations - Summary of Source of Funds (Detail)</link:definition>
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<link:definition>1052 - Disclosure - Business Combinations - Schedule of Valuation of Net Assets Acquired (Detail)</link:definition>
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<link:roleType roleURI="http://www.mastech.com/role/BusinessCombinationsSummaryOfUnauditedProFormaResultsDetail" id="BusinessCombinationsSummaryOfUnauditedProFormaResultsDetail">
<link:definition>1053 - Disclosure - Business Combinations - Summary of Unaudited Pro Forma Results (Detail)</link:definition>
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<link:definition>1054 - Disclosure - Goodwill and Other Intangible Assets, net - Additional Information (Detail)</link:definition>
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<link:definition>1055 - Disclosure - Goodwill and Other Intangible Assets, net - Reconciliation of Goodwill (Detail)</link:definition>
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<link:definition>1056 - Disclosure - Goodwill and Other Intangible Assets - Components of Identifiable Intangible assets (Detail)</link:definition>
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<link:definition>1064 - Disclosure - Long-Term Payroll Tax Liability - Additional Information (Detail)</link:definition>
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<link:definition>1066 - Disclosure - Stock-Based Compensation - Additional Information (Detail)</link:definition>
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<link:definition>1067 - Disclosure - Stock-Based Compensation - Summary of Company's Stock Option Activity (Detail)</link:definition>
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<link:definition>1068 - Disclosure - Stock-Based Compensation - Summary of Information Regarding the Company's Outstanding and Exercisable Stock Options (Detail)</link:definition>
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<link:definition>1069 - Disclosure - Stock-Based Compensation - Summary of Assumptions with Respect to the Black-Scholes Option Pricing Model (Detail)</link:definition>
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<link:definition>1070 - Disclosure - Stock-Based Compensation - Summary of Mastech's Restricted Stock Unit Activity (Detail)</link:definition>
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<link:definition>1071 - Disclosure - Income Taxes - Components of Income Before Income Taxes (Detail)</link:definition>
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<link:roleType roleURI="http://www.mastech.com/role/IncomeTaxesProvisionForIncomeTaxesDetail" id="IncomeTaxesProvisionForIncomeTaxesDetail">
<link:definition>1072 - Disclosure - Income Taxes - Provision for Income Taxes (Detail)</link:definition>
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<link:definition>1073 - Disclosure - Income Taxes - Reconciliation of Income Taxes (Detail)</link:definition>
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<link:definition>1074 - Disclosure - Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail)</link:definition>
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<link:roleType roleURI="http://www.mastech.com/role/IncomeTaxesUnrecognizedTaxBenefitsRelatedToUncertainTaxPositionsDetail" id="IncomeTaxesUnrecognizedTaxBenefitsRelatedToUncertainTaxPositionsDetail">
<link:definition>1075 - Disclosure - Income Taxes - Unrecognized Tax Benefits Related to Uncertain Tax Positions (Detail)</link:definition>
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<link:roleType roleURI="http://www.mastech.com/role/IncomeTaxesAdditionalInformationDetail" id="IncomeTaxesAdditionalInformationDetail">
<link:definition>1076 - Disclosure - Income Taxes - Additional Information (Detail)</link:definition>
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<link:definition>1080 - Disclosure - Shareholders' Equity - Additional Information (Detail)</link:definition>
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<link:definition>1085 - Disclosure - Other Comprehensive Income (Loss)  - Summary Of Accumulated Other Comprehensive Income (Loss) (Detail)</link:definition>
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<link:definition>1088 - Disclosure - Fair Value Measurements - Schedule of Changes in Contingent Consideration Liability (Detail)</link:definition>
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