October 28, 2019

Andrew Allen
President and Chief Executive Officer
Gritstone Oncology, Inc.
5858 Horton Street, Suite 210
Emeryville, California 94608

       Re: Gritstone Oncology, Inc.
           Registration Statement on Form S-3
           Filed October 15, 2019
           File No. 333-234211

Dear Mr. Allen:

       We have limited our review of your registration statement to those
issues we have
addressed in our comments. In some of our comments, we may ask you to provide
us with
information so we may better understand your disclosure.

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

       After reviewing any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments.

Registration Statement on Form S-3 filed October 15, 2019

Description of Capital Stock
Choice of Forum, page 10

1.     We note that the forum selection provision in your amended and restated
certificate of
       incorporation states, and you disclose, that unless you consent in
writing, the Court of
       Chancery of the State of Delaware is the exclusive forum for certain
litigation, including
       any "derivative action." However, your amended and restated bylaws
states that if the
       Chancery Court does not have jurisdiction, the federal district court
for the District of
       Delaware or other state courts of the State of Delaware may serve as an
alternative forum.
       Please revise your disclosure to discuss whether your forum selection
provisions apply to
       actions arising under the Exchange Act. In that regard, we note that
Section 27 of the
       Exchange Act creates exclusive federal jurisdiction over all suits
brought to enforce any
 Andrew Allen
Gritstone Oncology, Inc.
October 28, 2019
Page 2
      duty or liability created by the Exchange Act or the rules and
regulations thereunder. If the
      provisions do not apply to actions arising under the Exchange Act, please
ensure that the
      exclusive forum provisions in your governing documents state this
clearly, or tell us how
      you will inform investors in future filings that the provisions do not
apply to any actions
      arising under the Exchange Act.
2.    You state that your amended and restated certificate of incorporation
provides that the
      U.S. federal district courts are the exclusive forum for the resolution
of any complaint
      asserting a cause of action arising under the Securities Act. We note
that Section 22 of the
      Securities Act creates concurrent jurisdiction for federal and state
courts over all suits
      brought to enforce any duty or liability created by the Securities Act or
the rules and
      regulations thereunder. Please revise to state that investors cannot
waive compliance with
      the federal securities laws and the rules and regulations thereunder.
3.    Please expand your disclosure to provide material risks related to the
increased costs to
      investors to bring a claim and that these provisions can discourage
claims or limit
      investors' ability to bring a claim in a judicial forum that they find
favorable.
        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
statement.

      Please contact Folake Ayoola, Senior Counsel, at (202) 551-3673 or Irene
Paik, Attorney
Advisor, at (202) 551-6553 with any other questions.



                                                            Sincerely,
FirstName LastNameAndrew Allen
                                                            Division of
Corporation Finance
Comapany NameGritstone Oncology, Inc.
                                                            Office of Life
Sciences
October 28, 2019 Page 2
cc:       Brian J. Cuneo
FirstName LastName