FORM 20-F ☐REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR 12(g)OF THE SECURITIES EXCHANGE ACT OF 1934 OR ☐ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THESECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THESECURITIES EXCHANGE ACT OF 1934 OR ☐SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OFTHE SECURITIES EXCHANGE ACT OF 1934 Date of event requiring this shell company report Commission file number 001–37928 (Exact Name of Registrant as Specified in Its Charter) ChipMOS TECHNOLOGIES INC.(Translation of Registrant’s Name into English) Republic of China(Jurisdiction of Incorporation or Organization) No. 1, R&D Road 1, Hsinchu Science ParkHsinchu 300-092, Taiwan, Republic of China(Address of Principal Executive Offices) Silvia SuVice President, Finance and Accounting Management Center ChipMOS TECHNOLOGIES INC.No. 1, R&D Road 1, Hsinchu Science ParkHsinchu 300-092, Taiwan, Republic of ChinaTelephone: +886-3-577-0055Facsimile: +886-3-566-8970(Name, Telephone, E-mail and/or Facsimile Number and Address of Company Contact Person) Common Shares, par value NT$10 per share*IMOS*The NASDAQ Global Select Market* Securities registered or to be registered pursuant to Section 12(g) of the Act: None(Title of Class) Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act:None(Title of Class) Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of theclose of the period covered by the annual report. As of December 31, 2023, 727,240,126 Common Shares, par value NT$10 each, were outstanding. Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the SecuritiesAct.Yes☐No☐ If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reportspursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.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 theregistrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90days.Yes☐No☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required tobe submitted pursuant to Rule 405 of Regulation S-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).Yes☐No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-acceleratedfiler, or an emerging growth company. See definition of “large accelerated filer”, “accelerated filer”, and“emerging growth company” in Rule 12b-2 of the Exchange Act. : Large Accelerated Filer☐Accelerated Filer☐Non-Accelerated Filer☐Emerging growth company☐ If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate bycheck mark if the registrant has elected not to use the extended transition period for complying with any new orrevised financial 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’sassessment of the effectiveness of its internal control over financial 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 financialstatements of the registrant included in the filing reflect the correction of an error to previously issued financialstatements.☐ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysisof incentive-based compensation received by any of the registrant’s executive officers during the relevantrecovery period pursuant to §240.10D-1(b).☐ Indicate by check mark which basis of accounting the registrant has used to prepare the financial statementsincluded in this filing. U.S. GAAP☐International Financial Reporting Standards as issuedby the International Accounting Standards Board☐Other☐ If “Other” has been checked in response to the previous question, indicate by check mark which financialstatement item the registrant has elected to follow. Item 17☐Item 18☐ If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Exchange Act).Yes☐No☐ * Not for trading, but only in connection with the listing on the NASDAQ Global Select Market of AmericanDepositary Receipts evidencingAmericanDepositary Shares(the“ADSs”),each representing 2