(Mark One)☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 For the fiscal year endedDecember 31,2024OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACTOF 1934 For transition period from __________to__________Commission file number001-36332 ALDEYRA THERAPEUTICS, INC.(Exact name of Registrant as Specified in Its Charter) Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.Yes☐No☒Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.Yes☐No☒ Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.Yes☒No☐Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).Yes☒No☐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 the “large accelerated filer,” “accelerated filer,” “non-accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of theExchange Act. Smaller reporting company☒Emerging Growth Company☐ 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 financialaccounting standards provided pursuant to section 13(a) of the Exchange Act.☐ If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correctionof an error to previously issued financial statements.☐ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’sexecutive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).Yes☐No☒ As of June 30, 2024, the last business day of the registrant’s last completed second quarter, the aggregate market value of the registrant’s Common Stock held by non-affiliates ofthe registrant was approximately$191,737,565, based on the closing price of the registrant’s Common Stock, as reported by The Nasdaq Capital Market. Shares of Common Stock held byeach executive officer, director and stockholders known by the registrant to be affiliated with such individuals based on public filings and other information known to the registrant havebeen excluded since such persons may be deemed affiliates. This determination of affiliate status is not necessarily a conclusive determination for other purposes. As of February 26, 2025 there were59,708,654shares of the registrant’s Common Stock issued and outstanding. DOCUMENTS INCORPORATED BY REFERENCE Specified portions of the registrant’s proxy statement with respect to the registrant’s 2024 Annual Meeting of Stockholders, which is to be filed pursuant to Regulation 14A within120 days after the end of the registrant’s fiscal year endedDecember 31, 2024, are incorporated by reference into Part III of this Annual Report on Form 10-K. Aldeyra Therapeutics, Inc.Annual Report on Form 10-KFor the Fiscal Year Ended December 31, 2024Table of Contents Part I Special Note Regarding Forward-Looking StatementsIndustry and Market DataItem 1.BusinessItem 1A.Risk FactorsItem 1B.Unresolved Staff CommentsItem 1C.CybersecurityItem 2.PropertiesItem 3.Legal ProceedingsItem 4.Mine Safety Disclosures Part II Item 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities88Item 6.[Reserved]88Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations89Item 7A.Quantitative and Qualitative Disclosures About Market Risk100Item 8.Financial Statements and Supplementary Data100Item 9.Changes in and Disagreements With Accountants on Accounting and Financial Disclosure100Item 9A.Controls and Procedures100Item 9B.Other Information101Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections101Part III Item 10.Directors, Executive Officers, and Corporate GovernanceItem 11.Executive CompensationItem 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder MattersItem 13.Certain Relationships a