EXHIBIT 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

Pursuant to 18 U.S.C. § 1350, as created by Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned officer of Webster Financial Corporation (the “Company”) hereby certifies that, to his knowledge on the date hereof:

(a)the Form 10-Q Report of the Company for the quarter ended March 31, 2023 filed on the date hereof with the Securities and Exchange Commission (the “Report”) fully complies with the requirements of Section 13(a) or Section 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and

(b)the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: May 8, 2023

/s/ John R. Ciulla

John R. Ciulla

President, Chief Executive Officer, and Director

Pursuant to Securities and Exchange Commission Release 33-8238, dated June 5, 2003, this certification is being furnished and shall not be deemed filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended or incorporated by reference in any registration statement of the Company filed under the Securities Act of 1933, as amended, except to the extent that the Company specifically incorporates it by reference.

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.