June 22, 2018

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549-4720

Re:	American Century ETF Trust (the "Registrant")
	1933 Act File No. 333-221045, Post-Effective Amendment No. 5 and
	1940 Act File No. 811-23305, Amendment No. 7 (collectively, the “Amendment”)

Ladies and Gentlemen:

Pursuant to Section 101(a) of Regulation S-T and Rule 485(a) under the Securities Act of 1933, the aforementioned Registrant hereby submits for filing the following Amendment to the Registration Statement on Form N-1A.

The principal purposes of this Amendment are to: (i) add a new series of the Registrant, American Century Diversified Municipal Bond ETF, and (ii) make certain other non-material changes deemed appropriate by the Registrant.

If there are any questions or comments regarding this filing, please contact the undersigned at (816) 340-3275.

Sincerely,

/s/ Ashley L. Bergus

Ashley L. Bergus

Corporate Counsel

American Century Investments
P.O. Box 410141, 4500 Main Street	1-800-345-2021 or 816-531-5575
Kansas City, MO 64141-0141	www.americancentury.com