Hormizd I was the third Sassanid King of Persia from 270/72 to 273.

He was the son of Shapur I (240??70/72), under whom he was governor of Khorasan, and appears in his wars against Rome (Historia Augusta, Trig. Tyr. 2, where N繹ldeke has corrected the name Odomastes into Oromastes, i.e. Hormizd).

In the Persian tradition of the history of Ardashir I (226??40 [died 241/42]), preserved in a Pahlavi text (N繹ldeke, Geschichte des Artachsir I. Papakan), Hormizd I is made the son of a daughter of Mithrak, a Persian dynast, whose family Ardashir had extirpated because the Magi had predicted that the restorer of the empire of Persia would come from his blood.

According to legend, this daughter alone was saved by a peasant