EXHIBIT 32.1

CERTIFICATION OF PRESIDENT AND CHIEF EXECUTIVE OFFICER

PURSUANT TO TITLE 18, UNITED STATES CODE, SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Frank G. Heard, President and Chief Executive Officer, of Gibraltar Industries, Inc. (the “Company”), certify, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, that:

The Quarterly Report on Form 10-Q of the Company for the quarter ended June 30, 2018 (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m); and

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

/s/ Frank G. Heard

Frank G. Heard

President and Chief Executive Officer

July 26, 2018

A signed original of this written statement required by Section 906 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.