Exhibit 5.1

Harney Westwood & Riegels

14th Floor, Alexandra House

18 Chater Road

Central

Hong Kong

Tel: +852 5806 7800

Fax: +852 5806 7810

3 November 2026

raymond.ng@harneys.com

+852 5806 7883

067861-0004-RLN

Masonglory Limited

c/o Ascentium (Cayman) Limited

4th Floor, Harbour Place

103 South Church Street, P.O. Box 10240

Grand Cayman KY1-1002

Cayman Islands

Dear Sir or Madam

Masonglory Limited (the Company)

We are lawyers qualified to practise in the Cayman Islands and have acted as Cayman Islands legal advisers to the Company in connection with the Company’s registration statement on Form F-1, including all amendments or supplements thereto, to be filed on or around the date of this opinion with the Securities and Exchange Commission (the Commission) under the United States Securities Act of 1933, as amended (the Securities Act) (the Registration Statement), relating to the resale, from time to time, by the selling shareholders named in the Registration Statement (the Selling Shareholders) of up to 3,378,000 class A ordinary shares of a par value of US$0.0008 each (the Class A Ordinary Shares) (the Resale Shares), consisting of (i) 1,377,000 Class A Ordinary Shares issued on 12 August 2026, and (ii) 667,000 Class A Ordinary Shares issued on 5 October 2026, and (iii) up to 1,334,000 Class A Ordinary Shares issuable upon exercise of the series A warrants and the series B warrants (the Warrant Shares). We are furnishing this opinion as Exhibit 5.1 to the Registration Statement.

For the purposes of giving this opinion, we have examined the Documents (as defined in Schedule 1) which we regard as necessary in order to issue this opinion. We have not examined any other documents, official or corporate records or external or internal registers and have not undertaken or been instructed to undertake any further enquiry or due diligence in relation to the transaction which is the subject of this opinion.

In giving this opinion we have relied upon the assumptions set out in Schedule 2 which we have not independently verified.

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Based solely upon the foregoing examinations and assumptions and upon such searches as we have conducted and having regard to legal considerations which we deem relevant, and subject to the qualifications set out in Schedule 3, we are of the opinion that under the laws of the Cayman Islands:

Existence and Good Standing. The Company is a company duly incorporated with limited liability, and is validly existing and in good standing under the laws of the Cayman Islands. The Company is a separate legal entity and is subject to suit in its own name.

Authorised Share Capital. Based on our review of the M&A (as defined in Schedule 1), the authorised share capital of the Company is US$50,000 divided into 62,500,000 shares of a nominal or par value of US$0.0008 each, comprising (i) 60,000,000 class A ordinary shares of a par value of US$0.0008 each and (ii) 2,500,000 class B ordinary shares of a par value of US$0.0008 each.

Valid Issuance of Resale Shares. The Resale Shares to be offered and sold by the Selling Shareholders from time to time as contemplated by the Registration Statement have been duly authorised and, when allotted, issued and fully paid for in accordance with the Registration Statement, and when the names of the shareholders are entered in the register of members of the Company, the Resale Shares will be validly issued, fully paid and non-assessable, , and there will be no further obligation on the holders of any of the Resale Shares to make any further payment to the Company in respect of such Resale Shares.

Valid Issuance of Warrant Shares. The allotment and issuance of the Warrant Shares as contemplated by the Registration Statement have been duly authorised and, when allotted, issued and fully paid for in accordance with the Registration Statement, and when the names of the shareholders are entered in the register of members of the Company, the Warrant Shares will be validly issued, allotted, fully paid and non-assessable.

Cayman Islands Law. The statements under the headings “Description of Share Capital”, “Material Income Tax Consideration”, “Enforceability of Civil Liabilities” and “Legal Matters” in the prospectus forming part of the Registration Statement, to the extent that they constitute statements of Cayman Islands law, are accurate in all material respects as at the date of this opinion and such statements constitute our opinion.

This opinion is confined to the matters expressly opined on herein and given on the basis of the laws of the Cayman Islands as they are in force and applied by the Cayman Islands courts at the date of this opinion. We have made no investigation of, and express no opinion on, the laws of any other jurisdiction. Except as specifically stated herein, we express no opinion as to matters of fact.

In connection with the above opinion, we hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference made to this firm in the Registration Statement under the headings “Material Income Tax Considerations”, “Enforceability of Civil Liabilities” and “Legal Matters” and elsewhere in the prospectus included in the Registration Statement. In giving such consent, we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act, or the Rules and Regulations of the Commission thereunder.

This opinion is limited to the matters referred to herein and shall not be construed as extending to any other matter or document not referred to herein.

This opinion shall be construed in accordance with the laws of the Cayman Islands.

Yours faithfully

/s/ Harney Westwood & Riegels
Harney Westwood & Riegels

Schedule 1

List of Documents and Records Examined

A copy of the certificate of incorporation of the Company dated 21 February 2024;

A copy of the second amended and restated memorandum and articles of association of the Company adopted by a special resolution of the Company passed on 31 July 2026 (the M&A);

A copy of the register of directors of the Company provided to us on 22 October 2026;

A copy of the certificate of good standing in respect of the Company issued by Registrar of Companies dated 23 October 2026;

A copy of executed unanimous written resolutions of the directors of the Company dated 3 November 2026 (the Resolutions);

The Register of Writs and other Originating Process of the Grand Court of the Cayman Islands (the Court Register) via the Court’s Digital System (as defined in Schedule 3) conducted on 3 November 2026 (the Court Search Date);

A copy of the certificate from a director of the Company dated 3 November 2026, a copy of which is attached hereto (the Director’s Certificate); and

A copy of the Registration Statement filed with the Commission on or about the date of this opinion.

(1 to 7 above are the Corporate Documents, and 1 to 8 above are the Documents).

Schedule 2

Assumptions

Authenticity of Documents. Copy documents or drafts of documents provided to us are true and complete copies of, or in the final forms of, the originals. All original Documents are authentic, all signatures, initials and seals are genuine.

Corporate Documents. All matters required by law to be recorded in the Corporate Documents are so recorded, and all corporate minutes, resolutions, certificates, documents and records which we have reviewed are accurate and complete, and all facts expressed in or implied thereby are accurate and complete as at the date of the passing of the Resolutions.

Director’s Certificate. The contents of the Director’s Certificate are true and accurate as at the date of this opinion and there is no information not contained in the Director’s Certificate that will in any way affect this opinion.

Court Search. The Court Register examined by us via the Court’s Digital System on the Court Search Date, constitutes a complete record of the proceedings for such period before the Grand Court of the Cayman Islands.

No Steps to Wind-up. The directors and shareholders of the Company have not taken any steps to appoint a liquidator of the Company and no receiver has been appointed over any of the Company’s property or assets.

Resolutions. The Resolutions passed as written resolutions have been duly executed (and where executed by a corporate entity, such execution has been duly authorised if so required) by or on behalf of each director or shareholder (as the case may be), and the signatures and initials thereon are those of a person or persons in whose name the Resolutions have been expressed to be signed. The Resolutions remain in full force and effect.

Unseen Documents. Save for the Documents provided to us there are no resolutions, agreements, documents or arrangements which materially affect, amend or vary the transactions envisaged in the Registration Statement.

Schedule 3

Qualifications

Foreign Statutes. We express no opinion in relation to provisions making reference to foreign statutes in the Registration Statement.

Commercial Terms. Except as specifically stated herein, we make no comment with respect to any representations and warranties which may be made by or with respect to the Company in any of the documents or instruments cited in this opinion or otherwise with respect to the commercial terms of the transactions the subject of this opinion.

Meaning of Non-Assessable. In this opinion the phrase non-assessable means, with respect to the issuance of shares, that a shareholder shall not, in respect of the relevant shares, have any obligation to make further contributions to the Company's assets (except in exceptional circumstances, such as involving fraud, the establishment of an agency relationship or an illegal or improper purpose or other circumstances in which a court may be prepared to pierce or lift the corporate veil).

Good Standing. The Company shall be deemed to be in good standing at any time if all fees (including annual filing fees) and penalties under the Companies Act have been paid and the Registrar of Companies has no knowledge that the Company is in default under the Companies Act.

Court Search. The search of the Court Register has been undertaken on a digital system made available through the Grand Court of the Cayman Islands (the Court’s Digital System), and through inadvertent errors or delays in updating the digital system (and/or the Register from which the digital information is drawn) may not constitute a complete record of all proceedings as at the Court Search Date and in particular may omit details of very recent filings. The Court Search of the Court Register would not reveal, amongst other things, an Originating Process filed with the Grand Court which, pursuant to the Grand Court rules or best practice of the Clerk of the Courts’ office, should have been entered in the Court Register but was not in fact entered in the Court Register (properly or at all), or any Originating Process which has been placed under seal or anonymised (whether by order of the Court or pursuant to the practice of the Clerk of the Courts’ office).

Annex

Director’s Certificate

Masonglory Limited

incorporated in the Cayman Islands

Company No. 407426

(the Company)

Director’s Certificate

This certificate is given by the undersigned in his/her capacity as a duly authorised director of the Company to Harney Westwood & Riegels in connection with a legal opinion in relation to the Company (the Legal Opinion). Capitalised terms used in this certificate have the meaning given to them in the Legal Opinion.

Harney Westwood & Riegels may rely on the statements made in this certificate as a basis for the Legal Opinion.

I, the undersigned, am a director of the Company duly authorised to issue this certificate. Under the constitutional documents of the Company, the business and affairs of the Company are conducted by the board of directors of the Company.

I, the undersigned, confirm in relation to the Company that:

(a)

the second amended and restated memorandum and articles of association of the Company adopted by a special resolution of the Company passed on 31 July 2026 (the M&A) remain in full force and effect and are otherwise unamended;

(b)

the unanimous written resolutions of the board of directors dated 3 November 2026 were executed by all the directors in the manner prescribed in the M&A, the signatures and initials thereon are those of a person or persons in whose name the resolutions have been expressed to be signed, are in full force and effect at the date hereof and have not been amended, varied or revoked in any respect; and

(c)

there is no contractual or other prohibition (other than as arising under Cayman Islands law) binding on the Company prohibiting it from allotting and issuing the Resale Shares and the Warrant Shares or otherwise performing its obligations under the Registration Statement.

You may assume that all of the information in this certificate remains true and correct unless and until you are notified otherwise in writing.

[Signature page to follow]

/s/ Xie Jinyu		3 November 2026
Name: Xie Jinyu		Date
Director