Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-3 of Integral Ad Science Holding Corp. of our report dated March 2, 2023 relating to the financial statements, which appears in Integral Ad Science Holding Corp.’s Annual Report on Form 10-K for the year ended December 31, 2022. We also consent to the reference to us under the heading “Experts” in such Registration Statement.

/s/ PricewaterhouseCoopers LLP

New York, New York

May 9, 2023