United States securities and exchange commission logo November 15, 2021 Armon Sharei, Ph.D. President and Chief Executive Officer SQZ Biotechnologies Co 200 Arsenal Yards Blvd, Suite 210 Watertown, Massachusetts 02472 Re: SQZ Biotechnologies Co Registration Statement on Form S-3 Filed November 12, 2021 File No. 333-260980 Dear Armon Sharei: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Michael Davis at 202-551-4385 or Celeste Murphy at 202-551-3257 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Peter N. Handrinos