SECURITIES AND EXCHANGE COMMISSION
                                WASHINGTON, D.C.

                                    FORM 8-A


               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                    PURSUANT TO SECTION 12(b) OR (g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

                      FIRST TRUST EXCHANGE-TRADED FUND III
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             (Exact name of registrant as specified in its charter)

              MASSACHUSETTS                            See Exhibit 1
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(State of Incorporation or Organization)   (I.R.S. Employer Identification No.)

120 East Liberty Drive, Suite 400,
         Wheaton, Illinois                               60187
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Address of Principal Executive Offices)                (Zip Code)

Securities to be registered pursuant to Section 12(b) of the Act:

           TITLE OF EACH CLASS                NAME OF EACH EXCHANGE ON WHICH
           TO BE SO REGISTERED                EACH CLASS IS TO BE REGISTERED

 Common Shares of Beneficial Interest,              NYSE Arca, Inc.
      $0.01 par value per share,
                  of
   First Trust Ultra Short Duration
             Municipal ETF

If this form relates to the registration of a class of securities pursuant to
Section 12(b) of the Exchange Act and is effective pursuant to General
Instruction A. (c), check the following box.--
[X]

If this form relates to the registration of a class of securities pursuant to
Section 12(g) of the Exchange Act and is effective pursuant to General
Instruction A. (d), check the following box.--
[ ]

Securities Act registration statement file number to which this form relates:
333-176976.





Securities to be registered pursuant to Section 12(g) of the Act:

                                      None
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                      TITLE OF EACH CLASS TO BE REGISTERED

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

ITEM 1. DESCRIPTION OF REGISTRANT'S SECURITIES TO BE REGISTERED

      The securities to be registered hereunder are common shares of beneficial
interest, $0.01 par value per share (the "Shares"), of First Trust Ultra Short
Duration Municipal ETF (formerly First Trust Enhanced Short Maturity Municipal
ETF) (the "Fund"), a series of First Trust Exchange-Traded Fund III (the
"Registrant"). An application for listing of the Shares of the Fund has been
filed with and approved by NYSE Arca, Inc. A description of the Shares is
contained in the Prospectus, which is a part of the Registration Statement on
Form N-1A (Registration Nos. 333-176976 and 811-22245), filed with the
Securities and Exchange Commission on August 17, 2018. Such description is
incorporated by reference herein.

ITEM 2. EXHIBITS

      Pursuant to the "Instruction as to Exhibits" of Form 8-A, no exhibits are
filed herewith or incorporated by reference.





                                   SIGNATURE

      Pursuant to the requirements of Section 12 of the Securities Exchange Act
of 1934, the Registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, thereto duly authorized.

                                      FIRST TRUST EXCHANGE-TRADED FUND III



                                      By: /s/ W. Scott Jardine
                                          -------------------------------------
                                          W. Scott Jardine, Secretary

October 25, 2018





                                   Exhibit 1

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                 FUND                       I.R.S. EMPLOYER IDENTIFICATION NO.
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   First Trust Ultra Short Duration                    83-1799379
             Municipal ETF
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