May 16, 2019

Lee Kalowski
Chief Financial Officer
Bicycle Therapeutics Ltd.
4 Hartwell Place
Lexington, Massachusetts 02421

       Re: Bicycle Therapeutics Ltd.
           Amendment No. 1 to Registration Statement on Form S-1
           Filed May 13, 2019
           File No. 333-231076

Dear Mr. Kalowski:

     We have reviewed your amended registration statement and have the

       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 these comments, we may have additional comments.

Amendment No. 1 to Form S-1 filed on May 31, 2019

Summary Consolidated Financial Data
Statement of Operations Data, page 13

1.     We note from your disclosure on page 11 that you intend to grant options
to purchase an
       aggregate of 1,311,061 ordinary shares to certain of your directors and
officers upon the
       effectiveness of this registration statement. Please expand your
disclosure to provide a
       narrative description of the pro forma effects of this transaction to
the extent that the grant
       would materially impact your net loss and pro forma net loss per share
attributable to
       ordinary shareholders, basic and diluted, in accordance with Article 11
of Regulation
       S-X. Your disclosure should include the impact of the transaction by
income statement
       line item, as applicable.
       You may contact Jim Dunn at (202) 551-3724 or Isaac Esquivel at (202)
551-3395 if you
have questions regarding comments on the financial statements and related
matters. Please
 Lee Kalowski
Bicycle Therapeutics Ltd.
May 16, 2019
Page 2

contact Liz Walsh at (202) 551-3696 or Chris Edwards at (202) 551-6761 with any

FirstName LastNameLee Kalowski
                                                         Division of
Corporation Finance
Comapany NameBicycle Therapeutics Ltd.
                                                         Office of Healthcare &
May 16, 2019 Page 2
cc:       Jonathan Schur
FirstName LastName