EXHIBIT 5.1

October 14, 2025

VolitionRx Limited

1489 West Warm Springs Road, Suite 110

Henderson, Nevada  89014

Re: Securities of VolitionRx Limited

Ladies and Gentlemen:

We have acted as counsel for VolitionRx Limited, a Delaware corporation (the “Company”), in connection with the offering by the Company of up to 13,282,500 shares (the “Firm Shares”) of the Company’s common stock, par value $0.001 (the “Common Stock”), together with accompanying warrants to purchase up to 13,282,500 shares of Common Stock (the “Investor Warrants” and the shares underlying the Investor Warrants, the “Investor Shares”), including up to 1,732,500 shares of Common Stock (the “Option Shares”) and accompanying warrants to purchase up to 1,732,500 shares of Common Stock (the “Option Warrants”) that may be sold pursuant to the exercise of an option by the underwriter to purchase additional securities, and the issuance to the underwriter of the offering of common stock purchase warrants to purchase up to 929,775 shares of Common Stock (including warrants to purchase up to 121,275 shares of Common Stock that may be issued in connection with the exercise of the underwriter’s option, the “Underwriter Warrants”) and the shares underlying the Underwriter Warrants (the “Underwriter Shares”), pursuant to a registration statement on Form S-3 (Registration Statement No. 333-283088) (the “Registration Statement”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), the prospectus dated November 8, 2024, as amended on April 11, 2025 and as declared effective by the Commission on April 18, 2025 (the “Base Prospectus”), and the prospectus supplement dated October 14, 2025, filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations of the Securities Act (the “Prospectus Supplement”). The Base Prospectus and the Prospectus Supplement are collectively referred to as the “Prospectus.” The Firm Shares, Investor Shares, Option Shares, and Underwriter Shares are collectively referred to herein as the “Shares.” The Investor Warrants and Underwriter Warrants are collectively referred to herein as the “Warrants.” All of the Shares and Warrants are to be sold by the Company in the manner described in the Registration Statement and the Prospectus. This opinion is being furnished in accordance with the requirements of Item 601(b)(5)(i) of Regulation S-K.

In connection with the preparation of this opinion, we have examined originals or copies, certified or otherwise identified to our satisfaction, of: (a) the corporate and organizational documents of the Company, including the Second Amended and Restated Certificate of Incorporation, as amended through the date hereof, and the Amended and Restated Bylaws of the Company, as amended through the date hereof, (b) the resolutions (the “Resolutions”) of the Board of Directors of the Company and committees thereof with respect to the issuance and sale of the Securities, (c) the Registration Statement and exhibits thereto, including the Prospectus comprising a part thereof, and (d) an executed copy of the Underwriting Agreement, dated as of October 10, 2025, by and between the Company and Newbridge Securities Corporation, including the exhibits thereto (the “Underwriting Agreement”). In addition, we have examined originals or copies, certified or otherwise identified to our satisfaction, of certain other corporate records, documents, instruments and certificates of public officials and of the Company, and we have made such inquiries of officers of the Company and public officials and considered such questions of law as we have deemed necessary for purposes of rendering the opinions set forth herein.

VolitionRx Limited

October 14, 2025

Page Two

We have assumed the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies thereof and the genuineness of all signatures. In making our examination of documents executed by parties other than the Company, we have assumed that each other party has the power and authority to execute and deliver, and to perform and observe the provisions of, such documents and has duly authorized, executed and delivered such documents, and that such documents constitute the legal, valid and binding obligations of each such party. As to questions of fact material to our opinions, we have relied upon the certificates of certain officers of the Company.

With regard to our opinion concerning the Warrants constituting valid and binding obligations of the Company:

With respect to the Investor Shares and Underwriter Shares, we express no opinion to the extent that, notwithstanding its current reservation of shares of Common Stock, future issuances of securities, including the Investor Shares and Underwriter Shares, of the Company and/or adjustments to outstanding securities, including the Warrants, of the Company may cause the Warrants to be exercisable for more shares of Common Stock than the number that remain authorized but unissued. Further, we have assumed the Exercise Price (as defined in the respective Warrants) will not be adjusted to an amount below the par value per share of the Common Stock.

VolitionRx Limited

October 14, 2025

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Based on the foregoing, and subject to the further limitations, qualifications and assumptions set forth herein we are of the opinion that (a) the Shares have been duly authorized and, upon issuance, delivery and payment therefor in the manner contemplated by the Resolutions, the Underwriting Agreement, the Warrants, the Registration Statement and the Prospectus, will be validly issued, fully paid and non-assessable, and (b) the Warrants, when issued in accordance with the Registration Statement and the Underwriting Agreement, will constitute valid and legally binding obligations of the Company.

We render this opinion only with respect to the General Corporation Law of the State of Delaware as in effect on the date hereof, and we express no opinion herein concerning the application or effect of the laws of any other jurisdiction. This opinion is limited to the matters stated herein, and no opinion is implied or may be inferred beyond the matters expressly stated herein.

We hereby consent to the use of this opinion as Exhibit 5.1 to the Company’s Current Report on Form 8-K, and further consent to the reference to us under the heading “Legal Matters” in the Registration Statement and any amendments thereto. By giving this consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act and the rules and regulations promulgated thereunder.

[Signature Page Follows]

VolitionRx Limited

October 14, 2025

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This opinion is intended solely for use in connection with the issuance and sale of the Shares and Warrants  pursuant to the Registration Statement and is not to be relied upon for any other purpose or delivered to or relied upon by any other person without our prior written consent. This opinion is rendered as of the date hereof and based solely on our understanding of facts in existence as of such date after the examination described in this opinion. We assume no obligation to advise you of any fact, circumstance, event or change in the law or the facts that may hereafter be brought to our attention whether or not such occurrence would affect or modify the opinions expressed herein.