<DOCUMENT>
<TYPE>485BXT
<SEQUENCE>1
<FILENAME>bxt_lunt.txt
<DESCRIPTION>POST-EFFECTIVE AMENDMENT
<TEXT>

     As filed with the Securities and Exchange Commission on June 22, 2018
================================================================================
                                            1933 Act Registration No. 333-125751
                                             1940 Act Registration No. 811-21774

                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933                      [ ]
Pre-Effective Amendment No. __                                               [ ]
Post-Effective Amendment No. 104                                             [X]
                                     and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940              [ ]
Amendment No. 104                                                            [X]


                        FIRST TRUST EXCHANGE-TRADED FUND
               (Exact name of registrant as specified in charter)
                       120 East Liberty Drive, Suite 400
                            Wheaton, Illinois 60187
              (Address of Principal Executive Offices) (Zip Code)


       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (800) 621-1675

                       W. Scott Jardine, Esq., Secretary
                        First Trust Exchange-Traded Fund
                           First Trust Advisors L.P.
                       120 East Liberty Drive, Suite 400
                            Wheaton, Illinois 60187
                    (Name and Address of Agent for Service)

                                    Copy to:
                               Eric F. Fess, Esq.
                             Chapman and Cutler LLP
                             111 West Monroe Street
                            Chicago, Illinois 60603


It is proposed that this filing will become effective (check appropriate box):

[ ] immediately upon filing pursuant to paragraph (b)
[X] on July 20, 2018 pursuant to paragraph (b)
[ ] 60 days after filing pursuant to paragraph (a)(1)
[ ] on (date) pursuant to paragraph (a)(1)
[ ] 75 days after filing pursuant to paragraph (a)(2)
[ ] on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

[X] this post-effective amendment designates a new effective date for a
    previously filed post-effective amendment.


<PAGE>


                  CONTENTS OF POST-EFFECTIVE AMENDMENT NO. 104

      This Registration Statement comprises the following papers and contents:

      The Facing Sheet

      The sole purpose of this filing is to delay the effectiveness of the
Registrant's Post-Effective Amendment No. 102, as it relates to the First Trust
Lunt U.S. Factor Rotation ETF, a series of the Registrant, until July 20, 2018.
Parts A, B and C of the Registrant's Post-Effective Amendment No. 102 under the
Securities Act of 1933 as it relates to the First Trust Lunt U.S. Factor
Rotation ETF, filed on April 11, 2018, are incorporated by reference herein.

      Signatures


<PAGE>


                                   Signatures

      Pursuant to the requirements of the Securities Act of 1933 and the
Investment Company Act of 1940, the Registrant certifies that it meets all of
the requirements for effectiveness of this Registration Statement under rule
485(b) under the Securities Act and has duly caused this Registration Statement
to be signed on its behalf by the undersigned, duly authorized, in the City of
Wheaton, and State of Illinois, on the 22nd day of June, 2018.

                                        FIRST TRUST EXCHANGE-TRADED FUND


                                        By: /s/ James M. Dykas
                                        ----------------------------------------
                                        James M. Dykas, President and Chief
                                        Executive Officer


      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the date indicated:

SIGNATURE                  TITLE                                 DATE
                           President and Chief Executive         June 22, 2018
/s/ James M. Dykas         Officer
-------------------------
    James M. Dykas
                           Treasurer, Chief Financial Officer    June 22, 2018
/s/ Donald P. Swade        and Chief Accounting Officer
-------------------------
    Donald P. Swade
                                            )
James A. Bowen*                     Trustee )
                                            )
                                            )
Richard E. Erickson*                Trustee )
                                            )
                                            )      BY: /s/ W. Scott Jardine
Thomas R. Kadlec*                   Trustee )         ---------------------
                                            )          W. Scott Jardine
                                            )          Attorney-In-Fact
Robert F. Keith*                    Trustee )          June 22, 2018
                                            )
                                            )
Niel B. Nielson *                   Trustee )
                                            )

* Original powers of attorney authorizing James A. Bowen, W. Scott Jardine,
James M. Dykas, Eric F. Fess and Kristi A. Maher to execute Registrant's
Registration Statement, and Amendments thereto, for each of the trustees of the
Registrant on whose behalf this Registration Statement is filed, have been
previously filed and are incorporated by reference herein.

</TEXT>
</DOCUMENT>