ATHE 6-K

SECURITIESAND EXCHANGE COMMISSION

Washington,D.C. 20549

FORM6-K

REPORTOF FOREIGN PRIVATE ISSUER

PURSUANTTO RULE 13a-16 OR 15d-163

UNDERTHE SECURITIES EXCHANGE ACT OF 1934

Forthe month of November 21, 2025

AlterityTherapeutics Limited

(Name of Registrant)

Level 14, 350 Collins Street,Melbourne, Victoria 3000 Australia

(Address of Principal Executive Office)

Indicateby 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 ☐

ThisForm 6-K is being incorporated by reference into our Registration Statement on Form S-8 (Files No. 333-251073,333-248980 and 333-228671)and our Registration Statements on Form F-3 (Files No. 333-274816,333-251647, 333-231417and 333-250076)

ALTERITYTHERAPEUTICS LIMITED

(adevelopment stage enterprise)

The following exhibits are submitted:

1

SIGNATURE

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.

Date: November 21, 2025

2

Exhibit 99.1

Results of 2025 Annual General Meeting

MELBOURNE, AUSTRALIA AND SAN FRANCISCO, USA- 21 November 2025: In accordance with ASX Listing rule 3.13.2 and Section 251AA of the Corporations Act 2001 (Cth), the attached information is provided in relation to the resolutions passed by the shareholders of Alterity Therapeutics Limited (ASX: ATH, NASDAQ: ATHE) (“Alterity” or “the Company”) at its Annual General Meeting held on 21 November 2025.

About Alterity Therapeutics Limited

Alterity Therapeutics is a clinical stage biotechnology company dedicated to creating an alternate future for people living with neurodegenerative diseases. The Company is initially focused on developing disease modifying therapies in Parkinson’s disease and related disorders. Alterity has demonstrated clinically meaningful efficacy for its lead asset, ATH434, in a randomized, double blind, placebo-controlled Phase 2 clinical trial in participants with Multiple System Atrophy (MSA), a rare and rapidly progressive Parkinsonian disorder. ATH434 recently reported positive data in its open label Phase 2 clinical trial in advanced MSA. In addition, Alterity has a broad drug discovery platform generating patentable chemical compounds to treat the underlying pathology of neurological diseases. The Company is based in Melbourne, Australia, and San Francisco, California, USA. For further information please visit the Company’s website at www.alteritytherapeutics.com.

Authorisation & Additional information

This announcement was authorised by David Stamler, CEO of Alterity Therapeutics Limited.

Contacts:

Forward Looking Statements

This press release contains“forward-looking statements” within the meaning of section 27A of the Securities Act of 1933 and section 21E of the SecuritiesExchange Act of 1934. The Company has tried to identify such forward-looking statements by use of such words as “expects,” “intends,”“hopes,” “anticipates,” “believes,” “could,” “may,” “evidences” and “estimates,”and other similar expressions, but these words are not the exclusive means of identifying such statements.

Important factors thatcould cause actual results to differ materially from those indicated by such forward-looking statements are described in the sectionstitled “Risk Factors” in the Company’s filings with the SEC, including its most recent Annual Report on Form 20-F aswell as reports on Form 6-K, including, but not limited to the following: statements relating to the Company’s drug development program,including, but not limited to the initiation, progress and outcomes of clinical trials of the Company’s drug development program, including,but not limited to, ATH434, and any other statements that are not historical facts. Such statements involve risks and uncertainties, including,but not limited to, those risks and uncertainties relating to the difficulties or delays in financing, development, testing, regulatoryapproval, production and marketing of the Company’s drug components, including, but not limited to, ATH434, the ability of the Companyto procure additional future sources of financing, unexpected adverse side effects or inadequate therapeutic efficacy of the Company’sdrug compounds, including, but not limited to, ATH434, that could slow or prevent products coming to market, the uncertainty of obtainingpatent protection for the Company’s intellectual property or trade secrets, the uncertainty of successfully enforcing the Company’spatent rights and the uncertainty of the Company freedom to operate.

Any forward-looking statementmade by us in this press release is based only on information currently available to us and speaks only as of the date on which it ismade. We undertake no obligation to publicly update any forward-looking statement, whether written or oral, that may be made from timeto time, whether as a result of new information, future developments or otherwise.

2

3

4