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 July, 2023Commission File Number 001-15214

TRANSALTA CORPORATION

(Translation of registrant's name into English)

110-12th Avenue S.W., Box 1900, Station “M”,Calgary, Alberta, Canada, T2P 2M1

(Address of principal executive offices)

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 þ

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

Date: July 5, 2023

EXHIBIT INDEX

Exhibit 99.1

Media Advisory: TransAlta and TransAlta Renewables Second Quarter 2023 Results and Conference Call

CALGARY, AB, July 5, 2023 /CNW/ - TransAlta Corporation ("TransAlta") (TSX: TA) (NYSE: TAC) will release its second quarter 2023 results before markets open on Friday, August 4, 2023. A conference call and webcast to discuss the results will be held for investors, analysts, members of the media and other interested parties the same day beginning at 9:00 a.m. Mountain Time (11:00 a.m. ET). The media will be invited to ask questions following analysts.

TransAlta Renewables Inc. ("TransAlta Renewables") (TSX: RNW) will release its second quarter 2023 results before markets open on Thursday, August 3, 2023. Any questions regarding TransAlta Renewables may be asked on the TransAlta conference call.

Second Quarter 2023 ConferenceCall:Toll-free North American participants call: 1-888-664-6392Webcast link: https://app.webinar.net/QZL0W2G3RdB

Related materials will be available on the Investor Centre section of TransAlta's website at https://transalta.com/investors/presentations-and-events/. If you are unable to participate in the call, the instant replay is accessible at 1-888-390-0541 (Canada and USA toll free) with TransAlta pass code 650793 followed by the

sign. A transcript of the broadcast will be posted on TransAlta's website once it becomes available.

About TransAlta:

TransAlta owns, operates and develops a diversefleet of electrical power generation assets in Canada, the United States and Australia with a focus on long-term shareholder value. TransAltaprovides municipalities, medium and large industries, businesses and utility customers with clean, affordable, energy efficient and reliablepower. Today, TransAlta is one of Canada's largest producers of wind power and Alberta's largest producer of hydro-electric power. Forover 111 years, TransAlta has been a responsible operator and a proud member of the communities where we operate and where our employeeswork and live. TransAlta aligns its corporate goals with the UN Sustainable Development Goals and its climate change strategy with CDP(formerly Climate Disclosure Project) and the Task Force on Climate-related Financial Disclosures (TCFD) recommendations. TransAltahas achieved a 68 per cent reduction in GHG emissions or 22 million tonnes since 2015 and has received scores of A- from CDP and A fromMSCI.

For more information about TransAlta, visit itswebsite at transalta.com.

About TransAlta Renewables Inc.:

TransAlta Renewables is among the largest of anypublicly traded renewable independent power producers ("IPP") in Canada. Our asset platform and economic interests are diversifiedin terms of geography, generation and counterparties and consist of interests in 26 wind facilities, 13 hydroelectric facilities, eightnatural gas generation facilities, two solar facilities, one natural gas pipeline, and one battery storage project, representing an ownershipinterest of 2,968 megawatts of owned generating capacity, located in the provinces of British Columbia, Alberta, Ontario, Québec,New Brunswick, the States of Pennsylvania, New Hampshire, Wyoming, Massachusetts, Michigan, Minnesota, North Carolina, Washington andthe State of Western Australia.

For more information about TransAlta Renewables,visit its web site at transaltarenewables.com.

SOURCE TransAlta Corporation

View original content: http://www.newswire.ca/en/releases/archive/July2023/05/c2164.html

%CIK: 0001144800

For further information: Investor Inquiries: Phone: 1-800-387-3598 in Canada and U.S., Email: investor_relations@transalta.com; Media Inquiries: Toll-free media number: 1-855-255-9184, Email: ta_media_relations@transalta.com

CO: TransAlta Corporation

CNW 16:10e 05-JUL-23