September 11, 2018

Andrew Rasdal
Chief Executive Officer
Obalon Therapeutics, Inc.
5421 Avenida Encinas, Suite F
Carlsbad, California 92008

       Re: Obalon Therapeutics, Inc.
           Registration Statement on Form S-3
           Filed August 31, 2018
           File No. 333-227160

Dear Mr. Rasdal:

       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 Heather Percival at 202-551-3498 with any questions.



                                                            Sincerely,

                                                            Division of
Corporation Finance
                                                            Office of
Electronics and Machinery
cc:    B. Shayne Kennedy