Exhibit 23.3

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement on Form S-3 of Trustmark Corporation of our report dated February 20, 2020 relating to the consolidated financial statements and effectiveness of internal control over financial reporting appearing in the Annual Report on Form 10-K of Trustmark Corporation for the year ended December 31, 2019, and to the reference to us under the heading “Experts” in the prospectus.

/s/ Crowe LLP

Atlanta, Georgia

November 18, 2020