United States securities and exchange commission logo May 17, 2023 Sean Wirtjes Chief Financial Officer Rapid Micro Biosystems, Inc. 1001 Pawtucket Boulevard West, Suite 280 Lowell, MA 01854 Re: Rapid Micro Biosystems, Inc. Form 10-K for the fiscal year ended December 31, 2022 Filed March 10, 2023 File No. 001-40592 Dear Sean Wirtjes: We have completed our review of your filing. 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. Sincerely, Division of Corporation Finance Office of Industrial Applications and Services