Company: SLFQF
Filing Date: 2025-03-25
Form Type: 6-K
Source: 0001062993-25-006222
Chunk: 0

Company: SUN LIFE FINANCIAL INC
Filing Date: 2025-03-25
Form: 6-K
Chunk 0
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<div align='center'>UNITED STATESSECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 6-K

Report of Foreign Private Issuer
Pursuant to Rule 13a-16 or 15d-16
under the Securities Exchange Act of

1934</div>

| For the month of March, 2025 | Commission File Number: 001-15014 |

<div align='center'>SUN LIFE FINANCIAL INC.(Translation of registrant's name into English)

1 York Street, 31st Floor, Toronto, Ontario M5J 0B6(Address of principal executive offices)</div>

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-FForm 40-F

Exhibits

| 99.1 | Notice of Annual Meeting and Management Information Circular                                 |
| 99.2 | Notice and Access - Notice of Annual Meeting and Notice of Availability of Meeting Materials |
| 99.3 | Proxy Form and Request for Delivery of Financial Statements                                  |
| 99.4 | Electronic Distribution Insert                                                               |
| 99.5 | Annual Report                                                                                |

<div align='center'>SIGNATURE</div>

Pursuant to the requirements of the the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| Date: March 25, 2025 | Sun Life Financial Inc. 
 (Registrant)            
 By                      | /s/ Tracie Allan                               |
|:---------------------|:------------------------|:-----------------------------------------------|
|                      |                         | Tracie Allan                                   |
|                      |                         | VP, Associate General Counsel, Corporate Legal |