UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No.     )*

HUDSON TECHNOLOGIES, INC.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

444144109

(CUSIP Number)

June 6, 2014

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

x Rule 13d-1(c)

¨ Rule 13d-1(d)

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934, as amended (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications:

Taylor H. Wilson, Esq.

Haynes and Boone, LLP

2323 Victory Avenue, Suite 700

Dallas, Texas 75219

(214) 651-5000

CUSIP No. 444144109

Hudson Technologies, Inc.

1 Blue Hill Plaza, P.O. Box 1541, Pearl River, New York 10965

This statement is jointly filed by and on behalf of each of Becker Drapkin Management, L.P. (“BD Management”), Becker Drapkin Partners (QP), L.P. (“Becker Drapkin QP”), Becker Drapkin Partners, L.P. (“Becker Drapkin LP”), BC Advisors, LLC (“BCA”), Steven R. Becker (“Mr. Becker”) and Matthew A. Drapkin (“Mr. Drapkin,” and together with BD Management, Becker Drapkin QP, Becker Drapkin LP, BCA and Mr. Becker, the “Reporting Persons”). Becker Drapkin QP and Becker Drapkin LP are referred to collectively as the “Becker Drapkin Funds.”

Becker Drapkin QP has the power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the shares of common stock of the Issuer (the “Common Stock”) owned by it (the “Becker Drapkin QP Shares”). Becker Drapkin QP disclaims beneficial ownership of the Becker Drapkin LP Shares.

Becker Drapkin LP has the power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the Common Stock owned by it (the “Becker Drapkin LP Shares,” and together with the Becker Drapkin QP Shares, the “Becker Drapkin Funds Shares”). Becker Drapkin LP disclaims beneficial ownership of the Becker Drapkin QP Shares.

As general partner of each of the Becker Drapkin Funds, BD Management may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the Becker Drapkin Funds Shares. BD Management does not own any Common Stock directly and disclaims beneficial ownership of the Becker Drapkin Funds Shares.

As general partner of BD Management, BCA may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) any Common Stock beneficially owned by BD Management. BCA does not own any Common Stock directly and disclaims beneficial ownership of any Common Stock beneficially owned by BD Management.

As co-managing members of BCA, each of Mr. Becker and Mr. Drapkin may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) any Common Stock beneficially owned by BCA. Mr. Becker and Mr. Drapkin each hereby disclaim beneficial ownership of any Common Stock beneficially owned by BCA.

Each Reporting Person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act, the beneficial owner of any securities covered by this statement.

The address of the principal business office of each of the Reporting Persons is 500 Crescent Court, Suite 230, Dallas, Texas 75201.

See Item 4 on the cover page(s) hereto.

Common Stock

444144109

If filing as a non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J), please specify the type of institution:             

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following ¨.

Not Applicable.

Not Applicable.

Not Applicable.

Not Applicable.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect other than activities solely in connection with a nomination under §240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EXHIBIT INDEX

EXHIBIT 24.1

POWER OF ATTORNEY

June 16, 2014

Know all men by these presents, that each of Becker Drapkin Management, L.P., Becker Drapkin Partners (QP), L.P., Becker Drapkin Partners, L.P., BC Advisors, LLC, Steven R. Becker and Matthew A. Drapkin hereby constitutes and appoints Ashley Sekimoto, as the true and lawful attorney-in-fact and agent of such party with full power and authority and full power of substitution and resubstitution, for, in the name of, and on behalf of such party, place and stead, in any and all capacities, (i) to execute any and all filings required by such party under Section 13 or Section 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) (or any similar rule with respect to foreign exchanges) or any rule or regulation thereunder (including any amendment, supplement, and/or exhibit thereto), for, in the name of, and on behalf of such party, (ii) to do and perform any and all acts for, in the name of, and on behalf of such party which said attorney-in-fact determines may be necessary or appropriate to complete and execute any and all such filings, amendments, supplements and/or exhibits and any and all other document(s) in connection therewith, (iii) to file such filings, amendments, supplements, exhibits and/or documents with any governmental office or agency, whether U.S., foreign, state or local government (including, without limitation, the U.S. Securities and Exchange Commission and state securities administrators or commissions), or any stock exchange or stock quotation system, as may be required under applicable laws or rules and regulations of any stock exchange or stock quotation system, and (iv) to perform any and all other acts that said attorney-in-fact or agent determines may be necessary or appropriate in connection with the foregoing that may be in the best interest of or legally required by such party, granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as fully to all intents and purposes as such party might or could do in person, hereby ratifying and confirming all that said attorney-in-fact and agent shall do or cause to be done by virtue hereof. Each of Becker Drapkin Management, L.P., Becker Drapkin Partners (QP), L.P., Becker Drapkin Partners, L.P., BC Advisors, LLC, Steven R. Becker and Matthew A. Drapkin hereby acknowledges that the foregoing attorney-in-fact and agent in serving in such capacity at the request of such party, is not assuming any of the responsibilities of such party to comply with Section 16 or Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder.

IN WITNESS WHEREOF, each party hereto has caused this agreement to be executed and effective as of the date first written above.

EXHIBIT 99.1

JOINT FILING AGREEMENT

June 16, 2014

Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations thereunder, each party hereto hereby agrees to the joint filing, on behalf of each of them, of any filing required by such party under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder (including any amendment, restatement, supplement and/or exhibit thereto) with the Securities and Exchange Commission (and, if such security is registered on a national securities exchange, also with the exchange), and further agrees to the filing, furnishing and/or incorporation by reference of this agreement as an exhibit thereto. This agreement shall remain in full force and effect until revoked by any party hereto in a signed writing provided to each other party hereto, and then only with respect to such revoking party.

IN WITNESS WHEREOF, each party hereto, being duly authorized, has caused this agreement to be executed and effective as of the date first written above.