Hormizd I (flourished 3rd century) was the king of the Sāsānian empire (reigned ad 272–273); he was the son and successor of Shāpūr I. Known before his accession as Hormizd-Ardashīr, he acted as viceroy of the Persian province of Armenia. During Shāpūr’s capture of Antioch from the Romans after 256, Hormizd exercised important command, presumably earning his surname at that time. During his brief reign he was apparently tolerant of the activities of the religious leader Mani, founder of Manichaeism.