EXHIBIT (a)(1)(ii)

LETTER OF TRANSMITTAL

To Tender Preferred Shares

(Designated Auction Preferred Shares, Series A and Series B)

of

Eaton Vance Senior Income Trust

Pursuant to the Offer to Purchase

dated April 30, 2026

THE OFFER AND WITHDRAWAL RIGHTS EXPIRE AT 5:00 P.M., NEW YORK CITY
TIME, ON FRIDAY, MAY 29, 2026, UNLESS THE OFFER IS EXTENDED.

The Depositary for the Offer is:

Equiniti Trust Company, LLC

The Information Agent for the Offer is:

EQ Fund Solutions, LLC

28 Liberty Street, 53rd Floor
New York, New York 10005

(877) 732-3614

DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.

THE INSTRUCTIONS ACCOMPANYING THIS LETTER OF TRANSMITTAL SHOULD BE READ CAREFULLY BEFORE THIS LETTER OF TRANSMITTAL IS COMPLETED.

This Letter of Transmittal relates to the offer by Eaton Vance Senior Income Trust, a Massachusetts business trust (the “Fund”), to purchase for cash up to 100% of its outstanding preferred shares of beneficial interest, par value $0.01 per share and liquidation preference of $25,000 per share, designated Auction Preferred Shares, Series A and Series B (the “Preferred Shares”), upon the terms and subject to the conditions set forth in the Offer to Purchase dated April 30, 2026 (the “Offer to Purchase”), receipt of which is hereby acknowledged, and in this Letter of Transmittal, which, together with the Offer to Purchase, each as amended or supplemented from time to time, together constitute the “Offer.”

If you wish to tender all or any portion of your Preferred Shares of the Fund, you should either:

If you desire to tender Preferred Shares and such Preferred Shares cannot be delivered to the Depositary or you cannot comply with the procedure for book-entry transfer or your other required documents cannot be delivered to the Depositary, in any case, by the expiration of the Offer, you must tender such Preferred Shares pursuant to the guaranteed delivery procedure set forth in Section 4 of the Offer to Purchase.

Questions and requests for assistance or for additional copies of this Letter of Transmittal, the Offer to Purchase, the Notice of Guaranteed Delivery or the Notice of Withdrawal may be directed to EQ Fund Solutions, LLC, the information agent for the Offer, at its address or telephone number set forth on the first page of this Letter of Transmittal.

ADDITIONAL INFORMATION REGARDING TENDERED PREFERRED SHARES

PLEASE READ ACCOMPANYING INSTRUCTIONS CAREFULLY.

____________________________________________________________________________

Name(s) of Tendering Holder(s) of Preferred Shares ___________________________________

Date of Execution of Notice of Guaranteed Delivery ___________________________________

Name of Institution which Guaranteed Delivery ______________________________________

* If there is no established Auction Department, please include contact information for the party that submits auction instructions for Preferred Shares.

Ladies and Gentlemen:

The undersigned hereby tenders to Eaton Vance Senior Income Trust, a Massachusetts business trust (the “Fund”), the above-described preferred shares of beneficial interest, par value $0.01 per share and liquidation preference of $25,000 per share, designated Auction Preferred Shares, Series A and Series B (the “Preferred Shares”), pursuant to the Fund’s Offer to Purchase for cash up to 100% of its outstanding Preferred Shares (the “Offer”), upon the terms and subject to the conditions set forth in the Fund’s Offer to Purchase dated April 30, 2026, receipt of which is hereby acknowledged, and this Letter of Transmittal (which together constitute the “Offer Documents”). The price to be paid for the Preferred Shares is an amount per share, net to the seller in cash, equal to 98% of the liquidation preference of $25,000 per share (or $24,500 per share) (a 2% discount), plus any unpaid dividends accrued through May 29, 2026, or such later date to which the Offer is extended, less any applicable withholding taxes and without interest.

Upon the terms and subject to the conditions of the Offer and effective upon acceptance for payment of and payment for the Preferred Shares tendered herewith, the undersigned hereby sells, assigns and transfers to, or upon the order of, the Fund all right, title and interest in and to all the Preferred Shares that are being tendered hereby and appoints Equiniti Trust Company, LLC (the “Depositary”) the true and lawful agent and attorney-in-fact of the undersigned with respect to such Preferred Shares, with full power of substitution (such power of attorney being deemed to be an irrevocable power coupled with an interest), to:

(i) transfer ownership of such Preferred Shares on the account books maintained by the Book-Entry Transfer Facility (as defined in the Offer to Purchase), as applicable, together, in any such case, with all accompanying evidences of transfer and authenticity, to or upon the order of the Fund;

(ii) present such Preferred Shares for transfer on the Depositary’s books; and

(iii) receive all benefits and otherwise exercise all rights of beneficial ownership of such Preferred Shares, subject to the next paragraph, all in accordance with the terms of the Offer.

The undersigned hereby covenants, represents and warrants to the Fund that:

(i) the undersigned has full power and authority to tender, sell, assign and transfer the Preferred Shares tendered hereby and that when and to the extent the same are accepted for payment by the Fund, the Fund will acquire good, marketable and unencumbered title thereto, free and clear of all security interest, liens, restrictions, charges, encumbrances, conditional sales agreements or other obligations relating to the sale or transfer of the Preferred Shares and not subject to any adverse claims;

(ii) the undersigned understands that tenders of Preferred Shares pursuant to any of the procedures described in Section 4 of the Offer to Purchase and in the instructions to this Letter of Transmittal will constitute the undersigned’s acceptance of the terms and conditions of the Offer, including the undersigned’s representation and warranty that (a) the undersigned has a “net long position,” within the meaning of Rule 14e-4 promulgated under the Securities Exchange Act of 1934, as amended (“Rule 14e-4”), in the Preferred Shares or equivalent securities at least equal to the Preferred Shares being tendered, and (b) the tender of Preferred Shares complies with Rule 14e-4;

(iii) the undersigned will, upon request, execute and deliver any additional documents deemed by the Depositary or the Fund to be necessary or desirable to complete the sale, assignment and transfer of the Preferred Shares tendered hereby; and

(iv) the undersigned has read, understands and agrees to all the terms of the Offer.

All authority herein conferred or agreed to be conferred by this Letter of Transmittal shall survive the death or incapacity of the undersigned, and any obligation of the undersigned hereunder shall be binding upon the heirs, personal representatives, executors, administrators, successors, assigns, trustees in bankruptcy and legal representatives of the undersigned. Except as stated in the Offer to Purchase, this tender is irrevocable.

If any tendered Preferred Shares are not accepted for payment pursuant to the terms and conditions of the Offer for any reason, such Preferred Shares will be returned without expense to the holder of Preferred Shares (“Preferred Shareholder”) in accordance with Section 3 of the Offer to Purchase.

The undersigned understands that tenders of Preferred Shares pursuant to any one of the procedures described in Section 4 of the Offer to Purchase and in the instructions hereto will constitute a binding agreement between the undersigned and the Fund upon the terms and subject to the conditions of the Offer. The undersigned acknowledges that under no circumstances will the Fund pay interest on the purchase price, including, without limitation, by reason of any delay in making payment.

The undersigned recognizes that under the circumstances set forth in the Offer to Purchase, the Fund may terminate or amend the Offer; may postpone the acceptance for payment of, or the payment for, Preferred Shares tendered; or may accept for payment fewer than all of the Preferred Shares tendered.

A wire will be sent to the account at the Book-Entry Transfer Facility for the purchase price of any Preferred Shares purchased.

A non-U.S. Preferred Shareholder should NOT complete and return the attached IRS Form W-9, but should instead complete and return an appropriate IRS Form W-8. You may obtain an appropriate IRS Form W-8 at www.irs.gov. If you are unsure about which form to provide, please contact your tax adviser for the appropriate certification (e.g., IRS Form W-8BEN, W-8BEN-E, W-8IMY, W-8ECI or W-8EXP). Failure to provide an appropriate IRS Form W-8 will subject you to U.S. federal backup withholding tax at a rate of 24%. Non-U.S. Preferred Shareholders may also be subject to U.S. federal income tax withholding.

A non-U.S. Preferred Shareholder is any Preferred Shareholder other than (i) a citizen or resident of the United States, (ii) a corporation (or any other entity treated as a corporation for U.S. federal income tax purposes), partnership or other entity created or organized in or under the laws of the United States, any State thereof or the District of Columbia, (iii) an estate the income of which is subject to U.S. federal income taxation regardless of the source of the income, or (iv) a trust if (A) a court within the United States is able to exercise primary supervision over the administration of the trust and one or more “United States Persons” (as defined in the Internal Revenue Code of 1986, as amended) have the authority to control all substantial decisions of the trust or (B) the trust has a valid election in effect under applicable U.S. Treasury regulations to be treated as a U.S. person.

INSTRUCTIONS

Forming Part of the Terms and Conditions of the Offer

1. Guarantee of Signatures. Except as otherwise provided below, all signatures on this Letter of Transmittal must be guaranteed by a financial institution (including most banks, savings and loan associations and brokerage houses) that is a member of a recognized Medallion Program approved by The Securities Transfer Association, Inc., including the Securities Transfer Agents Medallion Program (STAMP), or any other “eligible guarantor institution” (as such term is defined in Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended) (each an “Eligible Institution”). Signatures on this Letter of Transmittal need not be guaranteed if such Preferred Shares are tendered for the account of an Eligible Institution. See Instruction 4.

2. Delivery of Preferred Shares. Delivery of Preferred Shares is to be made by book-entry delivery pursuant to the procedures set forth in Section 4 of the Offer to Purchase; an Agent’s Message (as defined in the Offer to Purchase) must be utilized. A confirmation of a book-entry transfer into the Depositary’s account at the Book-Entry Transfer Facility of all Preferred Shares delivered electronically, as well as an Agent’s Message, and any other documents required by this Letter of Transmittal, must be received by the Depositary at its address set forth on the front page of this Letter of Transmittal by the Expiration Date (as defined in the Offer to Purchase). Preferred Shareholders who cannot deliver their Preferred Shares and all other required documents to the Depositary by the Expiration Date must tender their Preferred Shares pursuant to the guaranteed delivery procedure set forth in Section 4 of the Offer to Purchase. Pursuant to such procedure: (i) such tender must be made by or through an Eligible Institution, (ii) a properly completed and duly executed Notice of Guaranteed Delivery substantially in the form provided by the Fund must be received by the Depositary by the Expiration Date and (iii) a properly completed and duly executed Letter of Transmittal (or facsimile thereof) with any required signature guarantee or an Agent’s Message and any other documents required by the Letter of Transmittal and, for Preferred Shares held in street name, confirmation of a book-entry transfer of such Preferred Shares into the Depositary’s account at the Book-Entry Transfer Facility, must be received by the Depositary within one New York Stock Exchange trading day after the date of execution of the Notice of Guaranteed Delivery, all as provided in Section 4 of the Offer to Purchase.

The method of delivery of any documents is at the option and risk of the tendering Preferred Shareholder. If delivery is by mail, registered mail with return receipt requested, properly insured, is recommended. In all cases, sufficient time should be allowed to ensure timely delivery.

No alternative, conditional or contingent tenders will be accepted, and no fractional Preferred Shares will be purchased. By executing this Letter of Transmittal, the tendering Preferred Shareholder waives any right to receive any notice of the acceptance for payment of the Preferred Shares.

3. Partial Tenders. If any tendered Preferred Shares are not accepted for payment pursuant to the terms and conditions of the Offer for any reason, or if any tendered Preferred Shares are not accepted because of an invalid tender, or if any tendered Preferred Shares are properly withdrawn, such Preferred Shares will be returned to the appropriate account at the Book-Entry Transfer Facility without charge by the Fund to the tendering Preferred Shareholder, as soon as practicable following expiration or termination of the Offer or the proper withdrawal of the Preferred Shares.

4. Stock Transfer Taxes. The Fund will pay any stock transfer taxes with respect to the sale and transfer of any Preferred Shares to it or its order pursuant to the Offer. If, however, a transfer tax is imposed for any reason other than the sale or transfer of Preferred Shares to the Fund pursuant to the Offer, then the amount of any such transfer taxes (whether imposed on the registered holder(s), such other person or otherwise) will be deducted from the purchase price unless satisfactory evidence of the payment of such taxes, or exemption therefrom, is submitted herewith.

5. IRS Tax Forms. Pursuant to U.S. federal income tax law, backup withholding tax at a rate of 24% may be imposed on the gross proceeds otherwise payable to Preferred Shareholders pursuant to the Offer. To avoid such backup withholding, each tendering Preferred Shareholder must provide the applicable withholding agent with such Preferred Shareholder’s correct taxpayer identification number (“TIN”) and certify that such Preferred Shareholder is not subject to such backup withholding by completing the attached IRS Form W-9 (or, in the case of a Non-U.S. Preferred Shareholder (as defined in the Offer to Purchase), an appropriate IRS Form W-8 or a valid substitute form). In general, if a Preferred Shareholder is an individual, the TIN is the individual’s Social Security number. If the applicable withholding agent is not provided with the correct TIN, the Preferred Shareholder will be subject to a $50 penalty unless the failure is due to reasonable cause and not willful neglect. If a Preferred Shareholder makes a false statement on an IRS Form W-9 without any reasonable basis that results in no backup withholding, such Preferred Shareholder will be subject to a $500 penalty, and the willful falsification of certifications or affirmations may be subject to criminal penalties, including fines and/or imprisonment. Certain Preferred Shareholders (including, among others, all corporations and certain non-U.S. individuals) are not subject to backup withholding. However, such Preferred Shareholders should complete an IRS Form W-9 (or, in the case of a Non-U.S. Preferred Shareholder, an appropriate IRS Form W-8 or a valid substitute form) to avoid erroneous backup withholding. For further information concerning backup withholding and instructions for completing an IRS Form W-9 (including how to obtain a TIN if you do not have one and how to complete an IRS Form W-9), consult the General Instructions found in IRS Form W-9.

A Non-U.S. Preferred Shareholder should not complete an IRS Form W-9. Such person should submit an appropriate IRS Form W-8 (or a valid substitute form) instead to establish that such non-U.S. person qualifies as an exempt recipient for which backup withholding is not required. These forms may be obtained from www.irs.gov.

Backup withholding is not an additional U.S. federal income tax. Rather, any U.S. federal income tax liability of a person subject to backup withholding generally will be reduced by the amount of tax withheld. If backup withholding results in an overpayment of taxes, a refund may be obtained from the IRS provided that the required information is timely furnished to the IRS.

NOTE: FAILURE TO PROVIDE A PROPERLY COMPLETED AND VALID IRS FORM W-9 OR AN APPROPRIATE IRS FORM W-8 OR A VALID SUBSTITUTE FORM, AS APPLICABLE MAY RESULT IN PENALTIES AND/OR BACKUP WITHHOLDING ON ANY AMOUNTS OTHERWISE PAYABLE TO YOU PURSUANT TO THE OFFER.

ANY TAX ADVICE CONTAINED IN THIS LETTER OF TRANSMITTAL (INCLUDING ANY ATTACHMENTS) IS NOT INTENDED OR WRITTEN TO BE USED, AND CANNOT BE USED, BY ANY TAXPAYER FOR THE PURPOSE OF AVOIDING TAX-RELATED PENALTIES UNDER THE INTERNAL REVENUE CODE OF 1986, AS AMENDED. EACH TAXPAYER SHOULD SEEK ADVICE BASED ON THE TAXPAYER’S PARTICULAR CIRCUMSTANCES FROM AN INDEPENDENT TAX ADVISOR. FOR ADDITIONAL INFORMATION, CONTACT YOUR TAX ADVISOR OR THE IRS.

6. Waiver of Conditions. Subject to the Offer to Purchase, the conditions of the Offer may be waived, in whole or in part, by the Fund, at any time and from time to time, in the case of any Preferred Shares tendered.

7. Irregularities. The Fund will determine, in its sole discretion, all questions as to the number of Preferred Shares to be accepted, and the validity, form, eligibility, including time of receipt, and acceptance for payment of any tender of Preferred Shares. The Fund’s determination will be final and binding on all parties. The Fund reserves the absolute right to reject any or all tenders it determines not to be in proper form or the acceptance of or payment for which it determines may be unlawful. The Fund also reserves the absolute right to waive any defect or irregularity in the tender of any particular Preferred Shares or any particular Preferred Shareholder. No tender of Preferred Shares will be deemed to be properly made until all defects or irregularities have been cured by the tendering Preferred Shareholder or waived by the Fund. None of the Fund, the Depositary, the Information Agent, or any other person will be under any duty to give notice of any defects or irregularities in any tender, or incur any liability for failure to give any such notice. The Fund’s interpretation of the terms of and conditions to the Offer, including this Letter of Transmittal and the instructions thereto, will be final and binding. By tendering Preferred Shares to the Fund, you agree to accept all decisions the Fund makes concerning these matters and waive any right you might otherwise have to challenge those decisions.

8. Acceptance of Tendered Shares. If a Preferred Shareholder tenders all of his or her Preferred Shares, all such Preferred Shares credited to such Preferred Shareholder’s account(s) will be tendered unless the Preferred Shareholder otherwise specifies.

9. Contact Information. In order to facilitate the Offer and any auctions for Preferred Shares that may remain outstanding after the Offer is completed, each broker or other Nominee Holder must provide additional contact information for its Auction Department, or whoever at the broker or other Nominee Holder submits auction instructions for the Preferred Shares on its behalf, and/or the Broker-Dealer, if a different party, that submits those auction instructions to the Auction Agent. If you are unable to provide this contact information, the Fund, in its sole discretion, may waive this requirement.

* * * * *

Any questions and requests for assistance may be directed to the Information Agent at its address and telephone number set forth on the first page of this Letter of Transmittal. Additional copies of the Offer to Purchase, the Letter of Transmittal and Notice of Guaranteed Delivery may be obtained from the Information Agent at its address and telephone number set forth on the first page of this Letter of Transmittal. Preferred Shareholders may also contact their broker, dealer, commercial bank or trust company or other nominee for assistance concerning the Offer.