ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal year ended December 31, 2025ORTRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934FOR THE TRANSITION PERIOD FROMtoCommission file number 001-36451 Quest Resource Holding Corporation(Exact Name of Registrant as specified in its Charter) 51-0665952(I.R.S. EmployerIdentification No.) Nevada(State or Other Jurisdiction ofIncorporation or Organization) 433 E. Las Colinas Boulevard, Suite 675Irving, Texas 75039(Address of Principal Executive Offices and Zip Code)(972) 464-0004(Registrant’s telephone number, including area code) Securities registered pursuant to Section 12(b) of the Act: Securities registered pursuant to Section 12(g) of the Act:None Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YesNo Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. YesNo 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 thepreceding 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 past90 days.YesNo Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of RegulationS-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files).YesNo 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 emerginggrowth company. See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company”, and “emerging growth company” in Rule 12b-2of the Exchange Act. Large accelerated filerNon-accelerated filerEmerging 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 revisedfinancial accounting standards provided pursuant to Section 13(a) of the Exchange Act. Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control overfinancial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its auditreport.☐ 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 reflectthe correction of 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 ofthe registrant’s executive 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 Exchange Act).YesNo The aggregate market value of the Common Stock held by non-affiliates of the Registrant, based on the closing price of such shares as quoted on the Nasdaq StockMarket on June 30, 2025 was $20,761,804. For purposes of this computation, all officers, directors, and 10% beneficial owners of the Registrant are deemed to beaffiliates. Such determination should not be deemed to be an admission that such officers, directors, or 10% beneficial owners are, in fact, affiliates of the Registrant.The number of shares of Registrant’s Common Stock outstanding as of March 2, 2026, was 20,959,751. TABLE OF CONTENTS PART I Item 1. Business1Item 1A. Risk Factors7Item 1B. Unresolved Staff Comments18Item 1C. Cybersecurity18Item 2. Properties19Item 3. Legal Proceedings19Item 4. Mine Safety Disclosures19 PART II Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities20Item 6. [Reserved]20Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations20Item 7A. Quantitative and Qualitative Disclosures About Market Risk28Item 8. Financial Statements and Supplementary Data28Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure28Item 9A. Controls and Procedures28Item 9B. Other Information28Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections28 PART III Item 10. Directors, Executive Officers and Corporate Governance29Item 11. Executive Compensation35Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters41Item 13. Certain Relationships