EXHIBIT A Power of Attorney for Section 16 Reporting Obligations Know all by these presents, that the undersigned hereby makes, constitutes and appoints each Robert R. Franklin, Jr., Paul P. Egge and Justin M. Long, or any of them acting singly, and with full power of substitution and re-substitution, the undersigned’s true and lawful attorney-in-fact (each of such persons and their substitutes being referred to herein as the “Attorney-in-Fact”), with full power to act for the undersigned and in the undersigned’s name, place and stead, in any and all capacities, to: 1. prepare, execute, and submit to the Securities and Exchange Commission (the “SEC”) a Form ID, including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of the reports required or considered by the Attorney-in-Fact to be advisable under Section 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or any rule or regulation of the SEC; 2. prepare, execute and submit to the SEC, Stellar Bancorp, Inc. (the “Company”), and/or any national securities exchange on which the Company’s securities are listed any and all reports (including any amendments thereto) the undersigned is required to file with the SEC, or which the Attorney-in-Fact considers advisable to file with the SEC, under Section 16 of the Exchange Act or any rule or regulation thereunder, or under Rule 144 (“Rule 144”) under the Securities Act of 1933, as amended, with respect to the any security of the Company, including Forms 3, 4 and 5, and Form 144; and 3. obtain, as the undersigned’s representative and on the undersigned’s behalf, information regarding transactions in the Company’s equity securities from any third party, including the Company and any brokers, dealers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such third party to release any such information to the Attorney-in-Fact. The undersigned acknowledges that: a) this Power of Attorney authorizes, but does not require, the Attorney-in-Fact to act in his or her discretion on information provided to such Attorney-in-Fact without independent verification of such information; b) any documents prepared or executed by the Attorney-in-Fact on behalf of the undersigned pursuant to this Power of Attorney will be in such form and will contain such information as the Attorney- in-Fact, in his or her discretion, deems necessary or desirable; c) neither the Company nor the Attorney-in-Fact assumes any liability for the undersigned’s responsibility to comply with the requirements of Section 16 of the Exchange Act or Rule 144, any liability of the undersigned for any failure to comply with such requirements, or any liability of the undersigned for disgorgement of profits under Section 16(b) of the Exchange Act; and d) this Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersigned’s obligations under Section 16 of the Exchange Act, including, without limitation, the reporting requirements Section 16 of the Exchange Act. The undersigned hereby grants to the Attorney-in-Fact full power and authority to do and perform each and every act and thing requisite, necessary or advisable to be done in connection with the foregoing, as fully, to all intents and purposes, as the undersigned might or could do in person, hereby ratifying and confirming all that the Attorney-in-Fact, or his or her substitute or substitutes, shall lawfully do or cause to be done by authority of this Power of Attorney.

134357650.1 - 2 - The undersigned also agrees to indemnify and hold harmless the Company and each such Attorney- in-Fact against any losses, claims, damages or liabilities (or actions in these respects) that arise out of or are based upon any untrue statements or omissions of necessary facts in the information provided by or at the direction of the undersigned, or upon the lack of timeliness in the delivery of information by or at the direction of the undersigned, to that Attorney-in-Fact for purposes of executing, acknowledging, delivering or filing any Forms 3, 4 or 5, or Form 144 (including any amendment thereto) and agrees to reimburse the Company and the Attorney-in-Fact on demand for any legal or other expenses reasonably incurred in connection with investigating or defending against any such loss, claim, damage, liability or action. This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 4 or 5 or Form 144 with respect to the undersigned’s holdings of and transactions in securities of the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Attorney-in-Fact. This Power of Attorney revokes all previous powers of attorney with respect to the subject matter of this Power of Attorney. [Signature Page Follows]

[Signature Page to Power of Attorney for Section 16 Reporting Obligations] IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney as of the date written below. /s/ Cynthia A. Dopjera Signature Cynthia A. Dopjera Print Name July 20, 2023 Date