Joseph Theodore Deters is an American politician and lawyer who has served as a justice of the Ohio Supreme Court since 2023.

The Supreme Court of the State of Ohio is the highest court in the U.S. state of Ohio, with final authority over interpretations of Ohio law and the Ohio Constitution. The court has seven members, a chief justice and six associate justices, who are elected at large by the voters of Ohio for six-year terms. The court has a total of 1,550 other employees. Since 2004, the court has met in the Thomas J. Moyer Ohio Judicial Center on the east bank of the Scioto River in Downtown Columbus. Prior to 2004, the court met in the James A. Rhodes State Office Tower and earlier in the Judiciary Annex of the Ohio Statehouse.