GSK GSK plc

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 March, 2025

Commission File Numbers: 001-15170; 001-35541; 001-34068

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-F ☐

THIS REPORT ON FORM 6-K SHALL BE DEEMED TO BE INCORPORATED BY REFERENCE IN THE PROSPECTUS INCLUDED IN THE REGISTRATION STATEMENT ON FORM F-3 (FILE NOS. 333-278205, 333-278205-01 AND 333-278205-02) OF GSK PLC, GLAXOSMITHKLINE CAPITAL PLC AND GLAXOSMITHKLINE CAPITAL INC. AND TO BE A PART THEREOF FROM THE DATE ON WHICH THIS REPORT IS FURNISHED, TO THE EXTENT NOT SUPERSEDED BY DOCUMENTS OR REPORTS SUBSEQUENTLY FILED OR FURNISHED.

GSK plc, GlaxoSmithKline Capital plc and GlaxoSmithKline Capital Inc. hereby incorporate by reference the following exhibits to this report on Form 6-K into their Registration Statement on Form F-3 (File Nos. 333-278205, 333-278205-01, 333-278205-02).

SIGNATURE

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 authorized.

Date: March 13, 2025

Exhibit 5.1

 March 13, 2025

GSK plc

79 New Oxford Street

London WC1A 1DG

United Kingdom

GlaxoSmithKline Capital Inc.

1100 North Market Street

Suite 4056, Wilmington

Delaware 19890

United States

GlaxoSmithKline Capital plc

79 New Oxford Street

London WC1A 1DG

United Kingdom

Ladies and Gentlemen:

We have acted as special United States counsel to GlaxoSmithKline Capital Inc., a Delaware corporation (“GSK Capital Inc.”), GlaxoSmithKline Capital plc, a public limited company incorporated in England and Wales (“GSK Capital plc”) and GSK plc, a public limited company incorporated in England and Wales (the “Guarantor”), in connection with the offering pursuant to a registration statement on Form F-3 (Nos. 333-278205, 333-278205-01 and 333-278205-02), as amended as of its most recent effective date (March 6, 2025), insofar as it relates to the Securities (as defined below) (as determined for purposes of Rule 430B(f)(2) under the Securities Act of 1933, as amended (the “Securities Act”)) (as so amended, including the documents incorporated by reference therein, but excluding Exhibits 25.1, 25.2 and 25.3, the “Registration Statement”) and the prospectus, dated March 25, 2024, as supplemented by the prospectus supplement thereto, dated March 6, 2025 (together, including the documents incorporated by reference therein, the “Prospectus”) of (i) guaranteed debt securities of GSK Capital Inc. consisting of U.S.$850,000,000 aggregate principal amount of 4.500% Notes due 2030 and U.S.$750,000,000 aggregate principal amount of 4.875% Notes due 2035 (together, the “GSK Capital Inc. Debt Securities”), (ii) guaranteed debt securities of GSK Capital plc consisting of U.S.$400,000,000 aggregate principal amount of 4.315% Notes due 2027 and U.S.$600,000,000 aggregate principal amount of Floating Rate Notes due 2027 (together, the “GSK Capital plc Debt Securities”, and together with the GSK Capital Inc. Debt Securities, the “Debt Securities”) and (iii) guarantees of the Guarantor in respect of the Debt Securities (the “Guarantees” and, together with the Debt Securities, the “Securities”).

Cleary Gottlieb Steen & Hamilton LLP is a Limited Liability Partnership registered in England and Wales Number OC310280. It is authorised and regulated

by the Solicitors Regulation Authority. A list of the members and their professional qualifications is open to inspection at the registered office,

2 London Wall Place, London EC2Y 5AU. Cleary Gottlieb Steen & Hamilton LLP or an affiliated entity has an office in each of the locations listed above.

GSK plc et al., p. 2

The GSK Capital Inc. Debt Securities and the related Guarantees were issued under an indenture dated as of April 6, 2004, as amended and supplemented by the First Supplemental Indenture dated as of March 18, 2013, as further amended and supplemented by the Second Supplemental Indenture dated as of March 21, 2014, and as further amended and supplemented by the Third Supplemental Indenture dated as of May 15, 2018, among GSK Capital Inc., the Guarantor and Deutsche Bank Trust Company Americas (as successor to Law Debenture Trust Company of New York, pursuant to an Instrument of Resignation, Appointment and Acceptance dated April 12, 2017, among GSK Capital Inc., Deutsche Bank Trust Company Americas and Law Debenture Trust Company of New York) as trustee (the “Trustee”) (the “GSK Capital Inc. Indenture”). The GSK Capital plc Debt Securities and the related Guarantees were issued under an indenture dated as of April 6, 2004, as amended and supplemented by the First Supplemental Indenture dated as of March 21, 2014, and as further amended and supplemented by the Second Supplemental Indenture dated as of May 15, 2018, among GSK Capital plc, the Guarantor and the Trustee (as successor to Law Debenture Trust Company of New York, pursuant to an Instrument of Resignation, Appointment and Acceptance dated April 12, 2017, among GSK Capital plc., the Trustee, and Law Debenture Trust Company of New York) (the “GSK Capital plc Indenture”, and together with the GSK Capital Inc. Indenture, the “Indentures”).

In arriving at the opinions expressed below, we have reviewed the following documents:

In addition, we have reviewed the originals or copies certified or otherwise identified to our satisfaction of all such corporate records of GSK Capital Inc. and such other documents, and we have made such investigations of law, as we have deemed appropriate as a basis for the opinions expressed below.

In rendering the opinions expressed below, we have assumed the authenticity of all documents submitted to us as originals and the conformity to the originals of all documents submitted to us as copies. In addition, we have assumed and have not verified the accuracy as to factual matters of each document we have reviewed.

GSK plc et al., p. 3

Based on the foregoing, and subject to the further assumptions and qualifications set forth below, it is our opinion that:

1. The GSK Capital Inc. Debt Securities in global form have been duly executed and delivered by GSK Capital Inc., and are the valid, binding and enforceable obligations of GSK Capital Inc., entitled to the benefits of the GSK Capital Inc. Indenture.

2. The GSK Capital plc Debt Securities in global form have been duly executed and delivered by GSK Capital plc under the law of the State of New York, and are the valid, binding and enforceable obligations of GSK Capital plc, entitled to the benefits of the GSK Capital plc Indenture.

3. The Guarantees have been duly executed and delivered by the Guarantor under the law of the State of New York and are the valid, binding and enforceable obligations of the Guarantor, entitled to the benefits of the GSK Capital Inc. Indenture and the GSK Capital plc Indenture, respectively.

Insofar as the foregoing opinions relate to the validity, binding effect or enforceability of any agreement or obligation of the Guarantor, GSK Capital Inc. or GSK Capital plc, (a) we have assumed that each of the Guarantor, GSK Capital Inc., GSK Capital plc and each other party to such agreement or obligation has satisfied those legal requirements that are applicable to it to the extent necessary to make such agreement or obligation enforceable against it (except that no such assumption is made as to the Guarantor, GSK Capital Inc. or GSK Capital plc regarding matters of the federal law of the United States of America or the law of the State of New York or, solely with respect to GSK Capital Inc., the General Corporation Law of the State of Delaware, that in our experience normally would be applicable to general business entities with respect to such agreement or obligation), (b) such opinions are subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally and to general principles of equity, (c) we express no opinion with respect to the effect of any mandatory choice of law rules and (d) in the case of the Guarantor and GSK Capital plc, such opinions are subject to the effect of judicial application of foreign laws or foreign governmental actions affecting creditors’ rights.

The waiver of defenses contained in Section 6.01 of each of the GSK Capital plc Indenture and the GSK Capital Inc. Indenture may be ineffective to the extent that any such defense involves a matter of public policy in New York.

We express no opinion as to the enforceability of Section 11.15 of each of the GSK Capital Inc. Indenture and the GSK Capital plc Indenture relating to currency indemnity.

The foregoing opinions are limited to the federal law of the United States of America, the law of the State of New York and the General Corporation Law of the State of Delaware. With respect to matters governed by the law of England and Wales, we have relied on our opinion dated March 13, 2025, as English counsel to GSK Capital Inc., GSK Capital plc and the Guarantor, which has been filed as Exhibit 5.2 to GSK Capital Inc.’s, GSK Capital plc’s and the Guarantor’s Form 6-K dated March 13, 2025.

We hereby consent to the filing of this opinion as an exhibit to the Current Report on Form 6-K of GSK Capital Inc., GSK Capital plc and the Guarantor dated March 13, 2025, and to the reference to us under the heading “Validity of Notes” in the Prospectus. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Securities and Exchange Commission thereunder.

GSK plc et al., p. 4

The opinions expressed herein are rendered on and as of the date hereof, and we assume no obligation to advise you or any other person, or to make any investigations, as to any legal developments or factual matters arising subsequent to the date hereof that might affect the opinions expressed herein.

Exhibit 5.2

 March 13, 2025

GSK plc

79 New Oxford Street

London WC1A 1DG

United Kingdom

GlaxoSmithKline Capital Inc.

1100 North Market Street

Suite 4056, Wilmington

Delaware 19890

United States

GlaxoSmithKline Capital plc

79 New Oxford Street

London WC1A 1DG

United Kingdom

Ladies and Gentlemen:

We have acted as special English counsel to GlaxoSmithKline Capital Inc., a Delaware corporation (“GSK Capital Inc.”), GlaxoSmithKline Capital plc, a public limited company incorporated in England and Wales (“GSK Capital plc”) and GSK plc, a public limited company incorporated in England and Wales (the “Guarantor”), in connection with the offering pursuant to a registration statement on Form F-3 (Nos. 333-278205, 333-278205-01 and 333-278205-02), as amended as of its most recent effective date (March 6, 2025), insofar as it relates to the Securities (as defined below) (as determined for purposes of Rule 430B(f)(2) under the Securities Act of 1933, as amended (the “Securities Act”)) (as so amended, including the documents incorporated by reference therein, but excluding Exhibits 25.1, 25.2 and 25.3, the “Registration Statement”) and the prospectus, dated March 25, 2024, as supplemented by the prospectus supplement thereto, dated March 6, 2025 (together, including the documents incorporated by reference therein, the “Prospectus”) of (i) guaranteed debt securities of GSK Capital Inc. consisting of U.S.$850,000,000 aggregate principal amount of 4.500% Notes due 2030 and U.S.$750,000,000 aggregate principal amount of 4.875% Notes due 2035 (together, the “GSK Capital Inc. Debt Securities”), (ii) guaranteed debt securities of GSK Capital plc consisting of U.S.$400,000,000 aggregate principal amount of 4.315% Notes due 2027 and U.S.$600,000,000 aggregate principal amount of Floating Rate Notes due 2027 (together, the “GSK Capital plc Debt Securities”, and together with the GSK Capital Inc. Debt Securities, the “Debt Securities”) and (iii) guarantees of the Guarantor in respect of the Debt Securities (the “Guarantees” and, together with the Debt Securities, the “Securities”).

Cleary Gottlieb Steen & Hamilton LLP is a Limited Liability Partnership registered in England and Wales Number OC310280. It is authorised and regulated

by the Solicitors Regulation Authority. A list of the members and their professional qualifications is open to inspection at the registered office,

2 London Wall Place, London EC2Y 5AU. Cleary Gottlieb Steen & Hamilton LLP or an affiliated entity has an office in each of the locations listed above.

GSK plc et al, p. 2

The GSK Capital Inc. Debt Securities and the related Guarantees were issued under an indenture dated as of April 6, 2004, as amended and supplemented by the First Supplemental Indenture dated as of March 18, 2013, as further amended and supplemented by the Second Supplemental Indenture dated as of March 21, 2014, and as further amended and supplemented by the Third Supplemental Indenture dated as of May 15, 2018, among GSK Capital Inc., the Guarantor and Deutsche Bank Trust Company Americas (as successor to Law Debenture Trust Company of New York, pursuant to an Instrument of Resignation, Appointment and Acceptance dated April 12, 2017, among GSK Capital Inc., Deutsche Bank Trust Company Americas and Law Debenture Trust Company of New York) as trustee (the “Trustee”) (the “GSK Capital Inc. Indenture”). The GSK Capital plc Debt Securities and the related Guarantees were issued under an indenture dated as of April 6, 2004, as amended and supplemented by the First Supplemental Indenture dated as of March 21, 2014, and as further amended and supplemented by the Second Supplemental Indenture dated as of May 15, 2018, among GSK Capital plc, the Guarantor and the Trustee (as successor to Law Debenture Trust Company of New York, pursuant to an Instrument of Resignation, Appointment and Acceptance dated April 12, 2017, among GSK Capital plc., the Trustee, and Law Debenture Trust Company of New York) (the “GSK Capital plc Indenture”, and together with the GSK Capital Inc. Indenture, the “Indentures”).

In arriving at the opinions expressed below, we have reviewed the following documents:

GSK plc et al, p. 3

GSK plc et al, p. 4

In addition, we have reviewed the originals, or copies certified or otherwise identified to our satisfaction, of all such other documents, and we have made such investigations of law, as we have deemed appropriate as a basis for the opinions expressed below.

GSK plc et al, p. 5

In this opinion letter, the Securities and the Indentures are referred to collectively as the “Transaction Documents” or each individually as a “Transaction Document”.

In rendering the opinions expressed below we have assumed and not verified:

GSK plc et al, p. 6

GSK plc et al, p. 7

Based on the foregoing, and subject to the further qualifications and limitations set forth below, it is our opinion that:

1. Each of the Guarantor and GSK Capital plc has been duly incorporated in and registered as a public limited company under the laws of England and Wales. A search of the records of the Registrar of Companies as made public through the www.companieshouse.gov.uk website on March 13, 2025 and an oral enquiry made to the Central Registry of Winding up Petitions at the Companies Court at approximately 10:48 AM GMT on March 13, 2025 revealed no petition, order or resolution for the winding up of either the Guarantor or GSK Capital plc and no petition for, and no notice of appointment of, a receiver or administrator, provided that:

GSK plc et al, p. 8

2. Each of the Guarantor and GSK Capital plc possesses the corporate power and authority to enter into and perform its obligations under each of the Transaction Documents to which it is a party.

3. The Indentures have been duly authorised, executed and delivered by the Guarantor.

4. The GSK Capital plc Indenture has been duly authorised, executed and delivered by GSK Capital plc.

We express no opinion as to any agreement, instrument or other document that may arise or be entered into, or as to any liability to tax or obligation to report to any tax authority that may arise or be incurred as a result of or in connection with the Transaction Documents, including, without limitation, the creation, issue or offer of the Debt Securities or the Guarantees or any other transaction.

The opinions set out above are limited to the laws of England and Wales in force as at the date of this opinion letter (taking into account the effect of the Agreement on the withdrawal of the United Kingdom of Great Britain and Northern Ireland from the EU and the European Atomic Energy Community and the EUWA), as currently applied by the courts in England and Wales, and are given on the basis that this opinion letter will be governed by and construed in accordance with English law. On January 31, 2020, the United Kingdom ceased to be a member of the European Union (the “EU”). By virtue of Sections 1A and 1B of the EUWA, EU law continued to be applicable in the United Kingdom for the duration of the implementation period set out in Section 1A(6) of the EUWA (“Transition Period”). After the Transition Period, pursuant to Sections 2 to 4 of the EUWA, certain EU laws in effect immediately before the end of the Transition Period form part of English law. However, EU law otherwise ceased to be applicable in the United Kingdom and thus does not form part of English law on and after January 1, 2021. The Retained EU Law (Revocation and Reform) Act 2023 came into effect on January 1, 2024 and, among other amendments, repealed section 4 of the EUWA and further restricted the scope of retained EU law in United Kingdom domestic law (now renamed ‘assimilated law’). We express no opinion on the effect of EU law in the United Kingdom or on EU law itself.

We hereby consent to the filing of this opinion as an exhibit to the Current Report on Form 6-K of the Guarantor, GSK Capital Inc. and GSK Capital plc dated March 13, 2025 and to the reference to us under the heading “Validity of Notes” in the Prospectus. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of

GSK plc et al, p. 9

the Securities and Exchange Commission thereunder. We assume no obligation to advise you or any other person, or to make any investigations, as to any legal developments or factual matters arising subsequent to the date hereof that might affect the opinions expressed herein.