As filed with the Securities and Exchange Commission on August 5, 2026

Registration No. 333-   

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

GERON CORPORATION

(Exact name of registrant as specified in its charter)

Geron Corporation 2018 Equity Incentive Plan

(Full title of the plans)

Harout Semerjian

President and Chief Executive Officer

Geron Corporation

919 E. Hillsdale Blvd, Suite 250

Foster City, California 94404

(650) 473-7700

(Name and address of agent for service) (Telephone number, including area code, of agent for service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE AND GENERAL INSTRUCTION E INFORMATION

This Registration Statement on Form S-8 is being filed by Geron Corporation (the “Registrant”) for the purpose of registering an additional 4,500,000 shares of the Registrant’s common stock, par value $0.001 per share (the “Common Stock”) issuable under the Registrant’s 2018 Equity Incentive Plan, as amended (the “2018 Incentive Plan”).

The additional shares of Common Stock registered hereunder for issuance under the Registrant’s 2018 Incentive Plan are of the same class as other securities for which a Registration Statement on Form S-8 has previously been filed by the Registrant and is effective. Accordingly, in accordance with General Instruction E of Form S-8, this Registration Statement incorporates by reference the contents of the following Registration Statements on Form S-8 previously filed by the Registrant: (i) File no. 333-225190, filed with the Securities and Exchange Commission (the “Commission”) on May 24, 2018; (ii) File no. 333-239324, filed with the Commission on June 19, 2020; (iii) File no. 333-258864, filed with the Commission on August  16, 2021; (iv) File no. 333-266795, filed with the Commission on August  11, 2022; (v) File no. 333-273669, filed with the Commission on August  3, 2023; and File no. 333-288433, filed with the Commission on June 30, 2025.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

The following documents filed by the Registrant with the Commission are incorporated by reference into this Registration Statement:

All reports and other documents filed by the Registrant pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on such form that relate to such items, after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference herein and to be a part of this Registration Statement from the date of filing such reports and documents. Any statement contained in a document incorporated or deemed to be incorporated herein by reference shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes that statement. Any such statement so modified or superseded shall not constitute a part of this Registration Statement, except as so modified or superseded.

Item 8. Exhibits

_____________________

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Foster City, State of California, on August 5, 2026.

GERON CORPORATION

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENT, that each person whose signature appears below constitutes and appoints Harout Semerjian, Michelle Robertson and Timothy Williams, and each of them, his or her true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in order to effectuate the same as fully, to all intents and purposes, as he or she might or could do in person, hereby ratifying and confirming all that each of said attorneys-in-fact and agents, or any of them, or their or his substitutes or substitute may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the date indicated.

Exhibit 5.1

Chadwick L. Mills

+1 650 843 5654

cmills@cooley.com

August 5, 2026

Geron Corporation

919 East Hillsdale Boulevard, Suite 250

Foster City, California 94404

Ladies and Gentlemen:

We have acted as counsel to Geron Corporation, a Delaware corporation (the “Company”) in connection with the filing of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission covering the offering of 4,500,000 shares (the “Shares”) of the Company’s Common Stock, par value $0.001 per share (the “Common Stock”), issuable pursuant to the Company’s 2018 Equity Incentive Plan (the “Plan”).

In connection with this opinion, we have examined and relied upon (a) the Registration Statement and the related prospectuses, (b) the Plan, (c) the Company’s certificate of incorporation and bylaws, each as currently in effect and (d) such other records, documents, opinions, certificates, memoranda and instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies thereof, the accuracy, completeness and authenticity of certificates of public officials, and the due authorization, execution and delivery of all documents by all persons other than by the Company. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plan, the Registration Statement and related prospectuses, will be validly issued, fully paid, and nonassessable (except as to Shares issued pursuant to deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

This opinion is limited to the matters expressly set forth in this letter, and no opinion has been or should be implied, or may be inferred, beyond the matters expressly stated. This opinion speaks only as to law and facts in effect or existing as of the date hereof, and we have no obligation or responsibility to update or supplement this letter to reflect any facts or circumstances that may hereafter come to our attention or any changes in law that may hereafter occur.

We consent to the filing of this opinion as an exhibit to the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Commission thereunder.

Cooley LLP 3 Embarcadero 20th Floor San Francisco, CA 94111-5800

t: (415) 693-2000 f: (415) 693-2222 cooley.com

August 5, 2026

Page Two

Cooley LLP 3 Embarcadero 20th Floor San Francisco, CA 94111-5800

t: (415) 693-2000 f: (415) 693-2222 cooley.com

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the 2018 Equity Incentive Plan, as amended, of Geron Corporation of our reports dated March 2, 2026, with respect to the consolidated financial statements of Geron Corporation and the effectiveness of internal control over financial reporting of Geron Corporation included in its Annual Report (Form 10-K) for the year ended December 31, 2025, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Boston, MA

August 5, 2026