November 15, 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
           Filed November 6, 2018
           File No. 333-228209

Dear Dr. Kroeger:

       We have limited our review of your registration statement to those
issues we have
addressed in our 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.

Form S-3 Filed November 6, 2018


1.     It appears that Section 5 of the Stock Purchase Agreement provides that
the purchaser has
       the option to waive Millendo's and OvaScience's obligations.
Additionally, the
       Explanatory Note in the registration statement indicating that you
expect this registration
       statement to become effective promptly after the closing of the
post-closing financing
       appears to imply a waiver of the Section 5.5 condition that the resale
       statement shall have been declared effective by the SEC. Therefore, it
does not appear
       that you have a valid exemption under Section 4(2) of the Securities Act
of 1933. You
       may withdraw the registration statement and refile it once the shares
are outstanding or
       amend the investment agreement to remove the investors' ability to waive
any of the
 Christopher A. Kroeger, M.D., M.B.A.
OvaScience, Inc.
November 15, 2018
Page 2
      closing conditions and refile your registration statement. For guidance,
refer to Securities
      Act Sections Compliance & Disclosure Interpretation 139.11.
        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.

       Refer to Rules 460 and 461 regarding requests for acceleration. Please
allow adequate
time for us to review any amendment prior to the requested effective date of
the registration

       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 15, 2018 Page 2
cc:       Megan Gates, Esq.
FirstName LastName