August 12, 2024

Geoff McDonough, M.D.
Chief Executive Officer
Generation Bio Co.
301 Binney Street
Cambridge, MA 02142

       Re: Generation Bio Co.
           Registration Statement on Form S-3
           Filed August 7, 2024
           File No. 333-281335
Dear Geoff McDonough M.D.:

       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 Tyler Howes at 202-551-3370 with any questions.



                                                           Sincerely,

                                                           Division of
Corporation Finance
                                                           Office of Life
Sciences
cc:   Molly W. Fox, Esq.