As filed with the Securities and Exchange Commission on October 22, 2021

1933 Act File No. 033-11387

1940 Act File No. 811-04984

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933			[ X ]
	Pre-Effective Amendment No.	[ ]
	Post-Effective Amendment No. 390	[ X ]
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940			[ X ]
	Amendment No. 391	[ X ]
(Check appropriate box or boxes.)

AMERICAN BEACON FUNDS

(Exact Name of Registrant as Specified in Charter)

220 East Las Colinas Boulevard, Suite 1200

Irving, Texas 75039

(Address of Principal Executive Offices) (Zip Code)

Registrant's Telephone Number, including Area Code: (817) 391-6100

Gene L. Needles, Jr., President

220 East Las Colinas Boulevard

Suite 1200

Irving, Texas 75039

(Name and Address of Agent for Service)

With copies to:

Kathy K. Ingber, Esq.

K&L Gates LLP

1601 K Street, NW

Washington, D.C. 20006-1600

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

[ ]	immediately upon filing pursuant to paragraph (b)
[ X ]	on November 21, 2021 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.

Explanatory Note

This Post-Effective Amendment No. 390 to the Registrant’s Registration Statement on Form N-1A is being filed pursuant to paragraph (b)(1)(iii) of Rule 485 of the Securities Act of 1933, as amended (the “1933 Act”), solely for the purpose of delaying, until November 21, 2021, the effectiveness of the registration statement for the American Beacon TwentyFour Strategic Income Fund and American Beacon TwentyFour Sustainable Short Term Bond Fund (the “Funds”), filed in Post-Effective Amendment No. 389 (“PEA No. 389”) on August 27, 2021, pursuant to paragraph (a) of Rule 485 of the 1933 Act. No other series of the Registrant is affected by the filing. Since no other changes are intended to be made to PEA No. 389 by means of this filing, Parts A, B and C of PEA No. 389 are incorporated herein by reference.

PART A – PROSPECTUS

The Prospectus for the Funds is incorporated herein by reference to Part A of PEA No. 389.

PART B – STATEMENT OF ADDITIONAL INFORMATION

The Statement of Additional Information for the Funds is incorporated herein by reference to Part B of PEA No. 389.

PART C – OTHER INFORMATION

The Part C for the Funds is incorporated herein by reference to Part C of PEA No. 389.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended (“1933 Act”), and the Investment Company Act of 1940, as amended, the Registrant represents that this Amendment meets all the requirements for effectiveness pursuant to Rule 485(b) under the 1933 Act and has duly caused this Post-Effective Amendment No. 390 to its Registration Statement on Form N-1A to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Irving and the State of Texas, on October 22, 2021.

	AMERICAN BEACON FUNDS

By:	/s/ Gene L. Needles, Jr.
	Gene L. Needles, Jr.
	President

Pursuant to the requirements of the 1933 Act, this Post-Effective Amendment No. 390 to the Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

Signature	Title	Date

/s/ Gene L. Needles, Jr.	President (Principal Executive Officer)	October 22, 2021
Gene L. Needles, Jr.

/s/ Sonia L. Bates	Treasurer (Principal Financial Officer	October 22, 2021
Sonia L. Bates	and Principal Accounting Officer)

Gilbert G. Alvarado*	Trustee	October 22, 2021
Gilbert G. Alvarado

Joseph B. Armes*	Trustee	October 22, 2021
Joseph B. Armes

Gerard J. Arpey*	Trustee	October 22, 2021
Gerard J. Arpey

Brenda A. Cline*	Chair and Trustee	October 22, 2021
Brenda A. Cline

Eugene J. Duffy*	Trustee	October 22, 2021
Eugene J. Duffy Claudia A. Holz*	Trustee	October 22, 2021
Claudia A. Holz
Douglas A. Lindgren*	Trustee	October 22, 2021
Douglas A. Lindgren

Barbara J. McKenna*	Trustee	October 22, 2021
Barbara J. McKenna

*By	/s/ Rosemary K. Behan¹
	Rosemary K. Behan
	Attorney-In-Fact

	¹Signed pursuant to previously filed power of attorney.