Power of Attorney for Nickolas Stavropoulos

This filing is an exhibit containing a Power of Attorney granted by Nickolas Stavropoulos, an officer and director of ONE Gas, Inc., to Regina L. Gregory and Brian K. Shore. The attorneys-in-fact are authorized to execute and file all Forms 3, 4, and 5 on behalf of Mr. Stavropoulos, as required by Section 16(a) of the Securities Exchange Act of 1934. This authorization includes taking any necessary actions to complete and file these forms with the SEC and any relevant authorities. The Power of Attorney remains in effect until Mr. Stavropoulos is no longer required to file these forms, unless revoked earlier in writing. It also revokes any previous powers of attorney granted for similar purposes. The filing confirms that neither ONE Gas, Inc. nor the designated attorneys-in-fact are assuming Mr. Stavropoulos's compliance responsibilities under Section 16.