UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of ~~the~~report ~~Securities~~(Date ~~Exchange~~of ~~Act~~earliest ofevent ~~1934~~reported): August 9, 2025

~~Date~~EATON ofVANCE ~~report~~SENIOR ~~(Date~~INCOME ~~of earliest event reported): October 18, 2023~~ TRUST

Eaton Vance Senior Income Trust

(Exact name of registrant as specified in its charter)

Massachusetts		811-09013	000000000
Massachusetts (State or other jurisdiction of incorporation)	811-09013 (Commission File Number)	04-3435040 (IRS Employer Identification No.)
(State or other jurisdiction of incorporation)		(Commission File Number)	(IRS Employer Identification No.)
One Post Office Square Boston, Massachusetts (Address of principal executive offices)		02109 (Zip Code)
Two International Place Boston, Massachusetts			02110
(Address of principal executive offices)			(Zip Code)

(617) 482-8260 (Registrant’s telephone number, including area code)

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐□ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐□ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐□ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐□ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Titles of Each Class	Trading Symbol	~~Trading~~Name ~~Symbol~~of exchange on which registered		~~Name of exchange on which registered~~
Common Shares of Beneficial Interest, $0.01 par value	EVF	~~EVF~~NYSE		~~New York Stock Exchange~~

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐ □

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ □

Item 8.01 Other Events

~~Effective~~Mr. ~~October 18,~~Mark ~~2023~~R. Fetting, ~~the~~who ~~Fund’s~~served as Chairperson of the Board of Trustees of ~~appointed~~the ~~Kenneth~~registrant A(the “Board”), unexpectedly passed away on August 9, 2025. ~~Topping~~Ms. Susan J. Sutherland is serving as ~~President~~acting Chairperson of the ~~Fund~~Board. ~~Set~~Effective ~~forth~~as ~~below~~of isAugust ~~certain information~~12, ~~with~~2025, ~~respect~~the toBoard ~~Mr.~~has ~~Topping:~~reduced the size of the Board from ten to nine members.

Name and Year of Birth		TrustPosition(s)		Length ofService		Principal Occupation(s) During Past Five Years
KENNETH A. TOPPING 1966		President		Since 2023		Vice President and Chief Administrative Officer of Eaton Vance and BMR and Chief Operating Officer for Public Markets at MSIM. Officer of 107 registered investment companies managed by Eaton Vance or BMR. Formerly, Chief Operating Officer for Goldman Sachs Asset Management ‘Classic’ (2009-2020).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~Eaton~~EATON ~~Vance~~VANCE ~~Senior~~SENIOR ~~Income~~INCOME ~~Trust By: /s/ Deidre E. Walsh Name: Deidre E. Walsh Title: Vice President & Chief Legal Officer~~TRUST

~~Date~~By: ~~October 18,~~ /s/ ~~2023~~Deidre E. Walsh

Name: Deidre E. Walsh

Title: Vice President & Chief Legal Officer

Date: August 14, 2025

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