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                           May 7, 2021

       Suying Liu
       Chairman, Chief Executive Officer, and Chief Financial Officer
       Mountain Crest Acquisition Corp. III
       311 West 43rd Street
       12th Floor
       New York, NY 10036

                                                        Re: Mountain Crest
Acquisition Corp. III
                                                            Registration
Statement on Form S-1
                                                            Filed April 27,
2021
                                                            File No. 333-255519

       Dear Dr. Liu:

              We have reviewed your registration statement and have the
following 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.

       Form S-1 filed April 27, 2021

       Financial Statements
       Notes to Financial Statements
       Note 6-Stockholder's Equity, page F-13

   1.                                                   We note your disclosure
here that you are authorized to issue 5,000,000 shares of common
                                                        stock with a par value
of $0.0001 per share. We also note similar disclosures on the
                                                        Balance Sheet, page F-3
and Capitalization Table, page 43. However, Paragraph 5 of
                                                        Exhibit 3.2, Amended
and Restated Certificate of Incorporation, indicates you are
                                                        authorized to issue
30,000,000 shares of common stock, $0.0001 par value. Please revise
                                                        or advise.
 Suying Liu
Mountain Crest Acquisition Corp. III
May 7, 2021
Page 2
General

2.    Your amended and restated certificate of incorporation provides that
"unless the
      Corporation consents in writing to the selection of an alternative forum,
the Court of
      Chancery of the State of Delaware shall be the sole and exclusive forum
for any
      stockholder (including a beneficial owner) to bring (i) any derivative
action or proceeding
      brought on behalf of the Corporation, (ii) any action asserting a claim
of breach of a
      fiduciary duty owed by any director, officer or other employee of the
Corporation to the
      Corporation or the Corporation   s stockholders, (iii) any action
asserting a claim against
      the Corporation, its directors, officers or employees arising pursuant to
any provision of
      the GCL or this Amended and Restated Certificate of Incorporation or the
Bylaws, or (iv)
      any action asserting a claim against the Corporation, its directors,
officers or employees
      governed by the internal affairs doctrine, except for, as to each of (i)
through (iv) above,
      (a) any claim as to which the Court of Chancery determines that there is
an indispensable
      party not subject to the jurisdiction of the Court of Chancery (and the
indispensable party
      does not consent to the personal jurisdiction of the Court of Chancery
within ten days
      following such determination), which is vested in the exclusive
jurisdiction of a court or
      forum other than the Court of Chancery, or for which the Court of
Chancery does not have
      subject matter jurisdiction, and (b) any action or claim arising under
the Exchange Act or
      Securities Act of 1933, as amended." Please revise your registration
statement to include
      disclosure related to this exclusive forum provision.
        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.

       You may contact Joanna Lam, Staff Accountant, at 202-551-3476 or Raj
Rajan, Staff
Accountant, at 202-551-3388 if you have questions regarding comments on the
financial
statements and related matters. Please contact Timothy Collins, Staff Attorney,
at 202-551-
3176 or Loan Lauren Nguyen, Legal Branch Chief, at 202-551-3642 with any other
questions.



                                                            Sincerely,
FirstName LastNameSuying Liu
                                                            Division of
Corporation Finance
Comapany NameMountain Crest Acquisition Corp. III
                                                            Office of Energy &
Transportation
May 7, 2021 Page 2
cc:       Giovanni Caruso
FirstName LastName