Exhibit 32.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the annual report on Form 10-K of Franklin Street Properties Corp. (the “Company”) for the period ended December 31, 2021 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, George J. Carter, Chief Executive Officer of the Company, hereby certifies, pursuant to 18 U.S.C. Section 1350, that, to his 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 operation of the Company.

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Date: February 15, 2022	/s/ George J. Carter
	George J. Carter
	Chief Executive Officer