EXHIBIT 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of First Guaranty Bancshares, Inc. (the “Company”) on Form 10-K as of and for the year ended December 31, 2016 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Alton B. Lewis, Chief Executive Officer of the Company, certify that to the best of my knowledge:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

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

/s/ Alton B. Lewis

Alton B. Lewis

Chief Executive Officer

(Principal Executive Officer)

March 30, 2017