UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the Month of December 2022

Commission File Number: 001-38547

Autolus Therapeutics plc

(Translation of registrant’s name into English)

The MediaWorks

191 Wood Lane

London W12 7FP

United Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

☒  Form 20-F            ☐  Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

INCORPORATION BY REFERENCE

The information contained in this Report, including Exhibit 99.1 of this Report, shall be deemed to be incorporated by reference into the registration statements on Form S-8 (File No. 333-226457), Form F-3 (File No. 333-258556), Form F-3 (File No. 333-264304), and Form F-3 (File No. 333-264650) of Autolus Therapeutics plc (the “Company”) and any related prospectuses, as such registration statements and prospectuses may be amended from time to time, and to be a part thereof from the date on which this Report is filed, to the extent not superseded by documents or reports subsequently furnished.

Press Release

On December 21, 2022, the Company issued a press release, a copy of which is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

Autolus Announces Partial Exercise of Underwriters’ Option to Purchase Additional ADSs

LONDON – 21 December 2022 – Autolus Therapeutics plc (Nasdaq: AUTL), a clinical-stage biopharmaceutical company developing next-generation programmed T cell therapies, announced today that the underwriters of its previously announced public offering of American Depositary Shares, or ADSs, which closed on December 13, 2022, have partially exercised their option to purchase an additional 6,927,102 ADSs, at a price per ADS of $2.00, resulting in additional gross proceeds to Autolus of approximately $13.9 million. After giving effect to the issuance of these additional shares, which closed today, Autolus has sold a total of 81,927,102 ADSs in the offering for aggregate gross proceeds of approximately $163.9 million.

Jefferies LLC, William Blair & Company L.L.C. and Wells Fargo Securities, LLC acted as joint bookrunners for the offering.

A preliminary prospectus supplement to the prospectus describing the terms of the offering was filed with the Securities and Exchange Commission, or the SEC, on December 8, 2022, and a final prospectus supplement was filed with the SEC on December 12, 2022. The offering of these ADSs is being made only by means of a written prospectus and prospectus supplement that form a part of the registration statement, which, for the avoidance of doubt, will not constitute a “prospectus” for the purposes of the Regulation (EU) 2017/1129 and has not been reviewed by any competent authority in any member state in the European Economic Area. Copies of the preliminary prospectus supplement and the accompanying prospectus relating to the offering may be obtained for free from the joint book-running managers for the offering, Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, 2nd Floor, New York, NY 10022, by telephone at (877) 821-7388 or by email at Prospectus_Department@Jefferies.com; William Blair & Company, L.L.C., Attention: Prospectus Department, 150 North Riverside Plaza, Chicago, IL 60606, by telephone at (800) 621-0687, or by email at prospectus@williamblair.com; or Wells Fargo Securities, LLC, Attention: Equity Syndicate Department, 500 West 33rd Street, New York, New York, 10001, at 833-690-2713 or email a request to cmclientsupport@wellsfargo.com.

This press release does not constitute an offer to sell or the solicitation of an offer to buy securities, and shall not constitute an offer, solicitation or sale in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of that jurisdiction.

About Autolus

Autolus is a clinical-stage biopharmaceutical company developing next-generation, programmed T cell therapies for the treatment of cancer. Using a broad suite of proprietary and modular T cell programming technologies, the company is engineering precisely targeted, controlled and highly active T cell therapies that are designed to better recognize cancer cells, break down their defense mechanisms and eliminate these cells. Autolus has a pipeline of product candidates in development for the treatment of hematological malignancies and solid tumors.

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Contacts:

Julia Wilson

+44 (0) 7818 430877

j.wilson@autolus.com

Susan A Noonan

S.A. Noonan Communications

+1-917-513-5303

susan@sanoonan.com