United States securities and exchange commission logo

                          March 17, 2021

       Todd C. Brady, M.D., Ph.D.
       Chief Executive Officer
       Aldeyra Therapeutics, Inc.
       131 Hartwell Avenue, Suite 320
       Lexington, MA 02421

                                                        Re: Aldeyra
Therapeutics, Inc.
Statement on Form S-3
                                                            Filed March 11,
                                                            File No. 333-254175

       Dear Dr. Brady:

              This is to advise you that we have not reviewed and will not
review your registration

               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 Ada D.
Sarmento at 202-551-3798 with any questions.


                          Division of Corporation Finance

                          Office of Life Sciences
       cc:                                              Keith J. Scherer, Esq.