Exhibit 99.8

Consent of Independent Registered Public Accounting Firm

We hereby consent to the incorporation by reference in this Annual Report on Form 40-F for the year ended September 30, 2022 of CGI Inc. of our report dated November 8, 2022, relating to the consolidated financial statements and the effectiveness of internal control over financial reporting, which appears in Exhibit 99.2 incorporated by reference in this Annual Report on Form 40-F.

We also consent to the incorporation by reference in the Registration Statements on Form S-8 Nos. 333-197742, 333-220741, 333-261831 and 333-261832 of CGI Inc. of our report dated November 8, 2022 referred to above.

We also consent to reference to us under the heading “Interests of Experts” which appears in Exhibit 99.1 incorporated by reference in this Annual Report on Form 40-F, which is incorporated by reference in such Registration Statements.

/s/ PricewaterhouseCoopers LLP

Montréal, Canada

December 16, 2022

PricewaterhouseCoopers LLP/s.r.l./s.e.n.c.r.l.

1250 René-Lévesque Boulevard West, Suite 2500, Montréal, Quebec, Canada H3B 4Y1

T: +1 514 205 5000, F: +1 514 876 1502, www.pwc.com/ca

“PwC” refers to PricewaterhouseCoopers LLP, an Ontario limited liability partnership.