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

I, Albert Seymour, Ph.D., President and Chief Executive Officer of Homology Medicines, Inc. (the “Company”) hereby certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

(1)The Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022 (the “Report”) fully complies with the requirements of Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

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

Date: March 9, 2023	By:	/s/ Albert Seymour, Ph.D.
		Albert Seymour, Ph.D.
		President, Chief Executive Officer and Director (Principal Executive Officer)