ANNUAL REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscalyear ended December 31, 2025 Commission file number 001-33013 FLUSHING FINANCIAL CORPORATION (Exact name of registrant as specified in its charter) 11-3209278(I.R.S. EmployerIdentification No.) Delaware(State or other jurisdiction ofincorporation or organization) 220 RXR Plaza, Uniondale, New York 11556(Address of principal executive offices) (718) 961-5400(Registrant’s telephone number, including area code) Securities registered pursuant to Section12(b)of the Act: Title of each classTrading Symbol(s)Name of each exchange on which registeredCommon Stock, $0.01 parvalueFFICThe NASDAQ StockMarket LLC Securities registered pursuant to Section12(g)of the Act: None. Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in rule405 of the Securities Act.☐Yes☒No Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d)of the Act.☐Yes☒No Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the Securities Exchange Act of 1934during the preceding 12months (or for such shorter period that the registrant was required to file such reports), and (2)has been subject to such filingrequirements for the past 90days.☒Yes☐No Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule405 ofRegulation S-T (§232.405 of this chapter) during the preceding 12months (or for such shorter period that the registrant was required to submit and postsuch 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 anemerging growth company. See definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growthcompany” in Rule12b-2 of the Exchange Act. Largeacceleratedfiler☐Non-acceleratedfiler☐ Accelerated filer☒Smallerreportingcompany☐Emerginggrowthcompany☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with anynew or revised financial accounting standards provided pursuant to Section13(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 internalcontrol over financial reporting under section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm thatprepared or issued its audit report.☒Yes☐No If securities are registered pursuant to Section12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in thefiling reflect the 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 compensationreceived by any of the 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 Rule12b-2 of the Act).☐Yes☒No As of June30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter; the aggregate market value of the votingstock held by non-affiliates of the registrant was$378,464,000. This figure is based on the closing price on that date on the NASDAQ Global SelectMarket for a share of the registrant’s Common Stock, $0.01 par value, which was $11.88. The number of shares of the registrant’s Common Stock outstanding as of February28, 2026 was33,883,626shares. DOCUMENTS INCORPORATED BY REFERENCE None Table of Contents INDEX Explanatory Note Part IIIItem10.Directors, Executive Officers and Corporate Governance2Item 11.Executive Compensation16Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters Stock Ownership42Item 13.Certain Relationships and Related Transactions Director Independence45Item 14.Principal Accounting Fees and Services46 Part IV Signatures Table of Contents EXPLANATORY NOTE Flushing Financial Corporation (the “Company”) is filing this Amendment No.1 on Form 10-K/A (this “Amendment”) to amend the Company’s AnnualReport on Form 10-K for the fiscal year ended December31, 2025 (the “Original Filing”), which was originally filed with the U.S. Securities andExchange Commission (the “SEC”) on March6, 2026 (the “Original Filing Date”). The Company is filing this Amendment to present the information required by Part III of Form 10-K as the Company may not file its definitive annualproxy statement within 120 days of the end of its fiscal year ended December31, 2025, and to supplement the exhibits contained in Item 15(