Company: RTNTF
Filing Date: 2025-10-14
Form Type: 6-K
Source: 0000863064-25-000018
Chunk: 0

Company: RIO TINTO LTD
Filing Date: 2025-10-14
Form: 6-K
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### FORM 6-K
<div align='center'>REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16</div>

#### UNDER THE SECURITIES EXCHANGE ACT OF 1934

#### October 14, 2025
| Commission file number: 001-10533               |     | Commission file number: 001-34121              |
| Rio Tinto plc                                   |     | Rio Tinto Limited                              |
|                                                 |     | ABN 96 004 458 404                             |
| (Translation of registrant’s name into English) |     | -Translation of registrant’s name into English |
| 6 St. James’s Square                            |     | Level 43, 120 Collins Street                   |
| London, SW1Y 4AD, United Kingdom                |     | Melbourne, Victoria 3000, Australia            |
| (Address of principal executive offices)        |     | -Address of principal executive offices        |

<div align='center'>Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F ☒ Form 40-F ☐</div>

### EXHIBITS
99.1 Stock Exchange announcement dated 14 October 2025 entitled ‘ Rio Tinto releases third quarter 2025 production results ’.

### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrants have duly caused this report to be signed on their behalf by the undersigned, thereunto duly authorised.

| Rio Tinto plc |     |                   |     | Rio Tinto Limited |     |                   |
| (Registrant)  |     |                   |     | -Registrant       |     |                   |
| By            |     | /s/ Andrew Hodges |     | By                |     | /s/ Tim Paine     |
| Name          |     | Andrew Hodges     |     | Name              |     | Tim Paine         |
| Title         |     | Company Secretary |     | Title             |     | Company Secretary |
| Date          |     | 14 October 2025   |     | Date              |     | 14 October 2025   |