Form 485BXT VANGUARD WELLESLEY INCOM

Explanatory Note

This Post-Effective Amendment No. 105 under the Securities Act of 1933, as amended (the “Securities Act”) (Amendment No. 105 under the Investment Company Act of 1940, as amended (the “1940 Act”)) to the registration statement on Form N-1A (the “Registration Statement”) of Vanguard Wellesley Income Fund (the “Trust”) is being filed pursuant to paragraph (b)(1)(iii) of Rule 485 under the Securities Act solely for the purpose of delaying, until March 23, 2026, the pending effective date of the Trust’s 102nd Post- Effective Amendment. By way of further background:

Post-Effective Amendment No. 102 was filed under Rule 485(a)(2) on November 24, 2025 to register shares of a suite of Vanguard Target Maturity Corporate Bond ETFs, each a new series of the Trust. Post-Effective Amendment No. 102 originally requested that the Amendment become effective 75 days after filing on February 7, 2026. Post-Effective Amendment No. 104 delayed the effective date until March 6, 2025.

This Post-Effective Amendment No. 105 incorporates by reference the information contained in Parts A, B, and C of Post-Effective Amendment No. 102 to the Registrant’s Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant hereby certifies that it meets all requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Town of Valley Forge and the Commonwealth of Pennsylvania, on the 5th day of March, 2026.

VANGUARD WELLESLEY INCOME FUND

BY: /s/ Salim Ramji*

Salim Ramji

Chief Executive Officer, President, and Trustee

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

*By: /s/ Natalie Lamarque

Natalie Lamarque, pursuant to a Power of Attorney filed on February 27, 2026 (see File Number 333-177613); and to a Power of Attorney, filed on December 19, 2025 (see File Number 333-11763), Incorporated by Reference.