As filed with the Securities and Exchange Commission on December 3, 2019

1933 Act Registration No. 333-176976

1940 Act Registration No. 811-22245

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. 105	[X]

First Trust Exchange-Traded Fund III

(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 III

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):

[X] immediately upon filing pursuant to paragraph (b)

[   ] on ____________ 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:

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

This Registration Statement relates to First Trust Municipal High Income ETF, First Trust Horizon Managed Volatility Developed International ETF, First Trust Horizon Managed Volatility Domestic ETF, First Trust California Municipal High Income ETF, First Trust Ultra Short Duration Municipal ETF and First Trust Short Duration Managed Municipal ETF, each a series of the Registrant.

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 3rd day of December, 2019.

First Trust Exchange-Traded Fund III
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
/s/ James M. Dykas	President and Chief Executive Officer		December 3, 2019
James M. Dykas
/s/ Donald P. Swade	Treasurer, Chief Financial Officer and Chief Accounting Officer		December 3, 2019
Donald P. Swade
James A. Bowen*	) Trustee )
	)
Richard E. Erickson*	) Trustee )
	)
Thomas R. Kadlec*	) Trustee )
	)	By:	/s/ W. Scott Jardine
Robert F. Keith*	) Trustee )		W. Scott Jardine Attorney-In-Fact
	)		December 3, 2019
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, are incorporated by reference herein.

Index to Exhibits

(101)       Risk/return summary in interactive data format