Company: SNY
Filing Date: 2025-10-24
Form Type: 6-K
Source: 0001121404-25-000026
Chunk: 0

Company: Sanofi
Filing Date: 2025-10-24
Form: 6-K
Chunk 0
---
### UNITED STATES

### SECURITIES 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

#### For the month of October 2025

#### Commission File Number: 001-31368

### SANOFI
<div align='center'>(Translation of registrant’s name into English)

46, avenue de la Grande Armée, 75017 Paris, FRANCE

(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.

<div align='center'>Form 20-F ☒ Form 40-F ☐</div>

In October 2025, Sanofi issued the press release attached hereto as Exhibit 99.1 which is incorporated herein by reference.

#### Exhibit Index
SIGNATURES

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, thereunto duly authorized.

| Dated: October 24, 2025 |     |        |     | SANOFI                            |
|:------------------------|:----|:-------|:----|:----------------------------------|
|                         |     | By:    |     | /s/ Alexandra Roger               |
|                         |     | Name:  |     | Alexandra Roger                   |
|                         |     | Title: |     | Head of Legal Corporate & Finance |