SUPPLEMENT DATED OCTOBER 3, 2023 TO THE

PROXY STATEMENT/ PROSPECTUS DATED JULY 20, 2023

TOUCHSTONE DYNAMIC ALLOCATION FUND

a series of

TOUCHSTONE STRATEGIC TRUST

303 Broadway, Suite 1100

Cincinnati, Ohio 45202

(800) 543-0407

TOUCHSTONE DYNAMIC INTERNATIONAL ETF

a series of

TOUCHSTONE ETF TRUST

303 Broadway, Suite 1100

Cincinnati, Ohio 45202

(800) 543-0407

The following information supplements and amends the Proxy Statement/Prospectus (the "Proxy Statement/Prospectus") furnished to shareholders of the Touchstone Dynamic Allocation Fund (the "Target Fund"), a series of Touchstone Strategic Trust (the "Target Trust"), and as filed with the U.S. Securities and Exchange Commission on July 20, 2023. The Proxy Statement/Prospectus was furnished to the Target Fund's shareholders in connection with the solicitation of proxies by the Board of Trustees of the Target Trust for a Special Meeting of Shareholders, which was originally scheduled to take place on August 29, 2023. As discussed in the Proxy Statement/Prospectus, shareholder approval of the reorganization of the Target Fund into the Touchstone Dynamic International ETF (the "Acquiring ETF"), a series of Touchstone ETF Trust (the "Reorganization"), is required. This supplement does not change the proposal to be considered at the Special Meeting, which is described in the Proxy Statement/Prospectus. Capitalized terms used in this supplement and not otherwise defined herein have the meaning given to them in the Proxy Statement/Prospectus.

Certain dates in connection with the Reorganization are hereby changed as noted below to reflect a delay in the Reorganization:

-The Special Meeting of Shareholders of the Target Fund has been adjourned to October 27, 2023 at 12:30 p.m. Eastern time at the offices of the Target Trust, 303 Broadway, Suite 1100, Cincinnati, Ohio 45202.

-The Reorganization is expected to be completed on or about December 1, 2023.

-The last trade day to redeem Target Fund shares will be trade date November 20, 2023.

-The Acquiring ETF will open for trading on or about December 4, 2023.

-Steps taken prior to the Reorganization:

oFirst, on or about November 10, 2023, each class of shares of the Target Fund will be consolidated into Class Y (without a contingent deferred sales charge or other charge).

Accordingly, after that date, all Target Fund shareholders will own Class Y shares.

oSecond, prior to the Reorganization on or about November 17, 2023, the Target Fund will conduct a reverse stock split pursuant to which approximately every 2.4 Class Y shares (as of December 31, 2022) will be merged (referred to as reverse split) into one Class Y share (the "Reverse Split"), with the exact ratio to be determined at the time of the Reorganization.

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oThird, on or about November 27, 2023, any fractional shares of the Target Fund held by shareholders will be redeemed, and the Target Fund will distribute such redemption proceeds to those shareholders.

* * * * *

There are no other changes to the Proxy Statement/Prospectus other than those date changes noted herein. This supplement does not revise or update any other information set forth in the Proxy Statement/Prospectus, and should be read in conjunction with the Proxy Statement/Prospectus. From and after the date of this supplement, any references to the "Proxy Statement/Prospectus" are to the Proxy Statement/Prospectus as supplemented hereby.

Please contact Shareholder Services at (800) 543-0407 or Morrow Sodali Fund Solutions, the proxy solicitor, at (888) 575-2251 for more information.

The date of this supplement is October 3, 2023.

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