November 20, 2018

Christopher A. Kroeger, M.D., M.B.A.
President and Chief Executive Officer
OvaScience, Inc.
9 Fourth Avenue
Waltham, MA 02451

       Re: OvaScience, Inc.
           Registration Statement on Form S-3
           Response dated November 16, 2018
           File No. 333-228209

Dear Dr. Kroeger:

       We have reviewed your November 16, 2018 response to our comment letter
and have the
following comment.

       Please respond to this letter by amending your registration statement
and providing the
requested information. If you do not believe our comment applies to your facts
circumstances or do not believe an amendment is appropriate, please tell us why
in your

       After reviewing any amendment to your registration statement and the
information you
provide in response to this comment, we may have additional comments. Unless we
otherwise, our references to prior comments are to comments in our November 15,
2018 letter.

Form S-3/A


1.     We note your response to comment 1. However, the result of the
purchasers' ability to
       waive unsatisfied conditions is that the purchasers have control over
closing conditions.
       Therefore, our comment is reissued. You may withdraw the registration
statement and
       refile it after the shares have been issued or you may renegotiate the
purchase agreement
       to remove the purchasers' right to waive unsatisfied conditions.
 Christopher A. Kroeger, M.D., M.B.A.
OvaScience, Inc.
November 20, 2018
Page 2

       You may contact Jeffrey Gabor at 202-551-2544 or Suzanne Hayes at
202-551-3675 with
any questions.

FirstName LastNameChristopher A. Kroeger, M.D., M.B.A.
                                                      Division of Corporation
Comapany NameOvaScience, Inc.
                                                      Office of Healthcare &
November 20, 2018 Page 2
cc:       Megan Gates, Esq.
FirstName LastName