March 12, 2020 Garry E. Menzel, Ph.D. Chief Executive Officer TCR2 Therapeutics Inc. 100 Binney Street, Suite 710 Cambridge, MA 02142 Re: TCR2 Therapeutics Inc. Registration Statement on Form S-3 Filed March 6, 2020 File No. 333-236965 Dear Dr. Menzel: 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 Paul Fischer at 202-551-3415 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Stephanie Richards, Esq.