6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Reportof Foreign Private Issuer Pursuant to Rule 13a-16 or 15d-16 of the SecuritiesExchange Act of 1934

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 x

INCORPORATION BY REFERENCE

Exhibits 99.1, 99.2, 99.3, 99.4, 99.5 and 99.6 of this Report on Form 6-K are incorporated by reference into the Registration Statement on Form F-10 (File No. 333-289110) of the Registrant, as amended or supplemented.

DOCUMENTS INCLUDED AS PART OF THIS REPORT

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.

Exhibit 99.1

CONSENT OF PATRICIO PINTO GALLARDO

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.

Exhibit 99.2

CONSENT OF ALEKSANDAR SPASOJEVIC

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.

Exhibit 99.3

CONSENT OF RANDAL M. BRUSH

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.

Exhibit 99.4

CONSENT OF ROBERT E. WILLIAMS, JR.

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.

Exhibit 99.5

CONSENT OF THOMAS WYNN ROGERS, JR.

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.

Exhibit 99.6

CONSENT OF RICHARD DELONG

The undersigned hereby consents to the use of the undersigned’s name and information derived from the Technical Report titled "South West Arkansas Project NI 43-101 Technical Report & Definitive Feasibility Study" dated October 14, 2025, with an effective date of September 3, 2025 (the “Technical Report”) and the incorporation by reference of the Technical Report into the Registration Statement on Form F-10 of Standard Lithium Ltd. (File No. 333-289110), as amended.