As filed with the Securities and Exchange Commission on May 20, 2025

Registration Statement No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

Under

THE SECURITIES ACT OF 1933

Inogen, Inc.

(Exact name of registrant as specified in its charter)

859 Ward Drive

Goleta, California 93111

(Address of principal executive offices)

Inogen, Inc. Amended and Restated 2023 Equity Incentive Plan

(Full title of the plan)

Kevin R.M. Smith

Chief Executive Officer and President

Inogen, Inc.

859 Ward Drive

Goleta, California 93111

(Name and address of agent for service)

(805) 562-0500

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

Copies to:

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, 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

This Registration Statement on Form S-8 (the “Registration Statement”) of Inogen, Inc. (the “Company” or the “Registrant”) registers an additional 750,000 shares of common stock of the Registrant, par value $0.001 per share (“Common Stock”), reserved for issuance pursuant to future awards under the Registrant’s Amended and Restated 2023 Equity Incentive Plan (the “2023 Plan”). This share increase was approved by the Company’s stockholders at an annual meeting of stockholders held on May 14, 2025. In accordance with Section E of the General Instructions to Form S-8, the contents of the previous registration statements on Form S-8 filed by the Registrant with the Securities and Exchange Commission (the “Commission”) on June 7, 2023 (File No. 333-272468) and June 12, 2024 (File No. 333-280151) are incorporated by reference herein, except to the extent supplemented, superseded or modified by the specific information set forth below or the specific exhibits attached hereto. In accordance with the instructional note to Part I of Form S-8 as promulgated by the Commission, the information specified by Part I of Form S-8 has been omitted from this Registration Statement.

PART II

INFORMATION REQUIRED IN REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

The Registrant is subject to the informational and reporting requirements of Sections 13(a), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and in accordance therewith files reports, proxy statements and other information with the Commission. The Registrant hereby incorporates by reference into this Registration Statement the following documents previously filed with the Commission:

All documents filed by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act on or after the date of this Registration Statement and prior to the filing of a post-effective amendment to this Registration Statement that indicates that all securities offered have been sold or that deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing of such documents; provided, however, that documents or information deemed to have been furnished and not filed in accordance with the rules of the Commission shall not be deemed incorporated by reference into this Registration Statement. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently filed document which also is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Item 8. Exhibits.

+ Indicates management contract or compensatory plan, contract or arrangement.

* Filed herewith.

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 Goleta, State of California, on May 20, 2025.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Kevin R.M. Smith and Michael Bourque, and each of them, as his or her true and lawful attorneys-in-fact and agents, 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 (including his or her capacity as a director and/or officer of Inogen, Inc.) to sign the Registration Statement on Form S-8 of Inogen, Inc., and any and all amendments (including post-effective amendments) thereto, and to file the same, with all exhibits thereto and all other documents in connection therewith, with the Securities and Exchange 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 connection therewith, as fully for all intents and purposes as they, he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their, his or her substitute or substitutes, 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 dates indicated.