Company: TSLTF
Filing Date: 2025-11-06
Form Type: 6-K
Source: 0001144800-25-000039
Chunk: 0

Company: TRANSALTA CORP
Filing Date: 2025-11-06
Form: 6-K
Chunk 0
---
#### FORM 6-K

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549
<div align='center'>REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16</div>

#### UNDER THE SECURITIES EXCHANGE ACT OF 1934
For the month of November 2025

Commission File Number 001-15214

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

Suite 1400, 1100 - 1st Street S.E., Calgary, Alberta, T2G 1B1

(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-F____ |     | Form 40-FX |

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):_____

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):_____

The documents listed below in this Section and filed as Exhibits 99.2 and 99.3 to this form 6-K are hereby filed with the Securities and Exchange Commission for the purpose of being and hereby are incorporated by reference into the following registration statements filed by TransAlta Corporation under the Securities Act of 1933, as amended:

#### Form

#### Registration No
.

S-8 333-72454

S-8 333-101470

S-8 333-236894

S-8 333-260935

F-10 333-271953

### 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.

| TRANSALTA CORPORATION                                         |
| /s/ Joel Hunter                                               |
| Joel Hunter                                                   |
| Executive Vice President, Finance and Chief Financial Officer |

Date: Nov. 5, 2025

### EXHIBIT INDEX
| 99.2 |     | Management’s Discussion and Analysis of Financial Condition and Results of Operations of the registrant as at and for the period ended Sept. 30, 2025. |
|