Peroz (Peirozes, Priscus, fr. 33; Perozes, Procop. Pers. I. 3 and Agath. iv. 27; the modern form of the name is Feroz, Firuz), Sassanid king of Persia, AD 457-484, son of Yazdegerd II.

He rebelled against his brother Hormizd III, and in 459 defeated and killed him with the help of the Ephthalites, or White Huns, who had invaded Bactria. He also killed most of his other relatives, and persecuted the Christians. But he favoured the introduction of Nestorianism, in opposition to the orthodox creed of the Byzantine Empire.

With the Romans he maintained peace, but he tried to keep down the Ephthalites, who began to conquer eastern Iran. The Romans supported him with subsidies; but all his wars were disastrous. Once he was himself taken prisoner and had to give his son Kavadh as hostage till after two years he was able to pay a heavy ransom.

Then he broke the treaty again and advanced with a large army. But he lost his way in the eastern desert and perished with his whole army (484). The Ephthalites invaded and plundered Persia for two years, till at last a noble Persian from the old family of Karen, Zarmihr (or Sokhra), restored some degree of order. He raised Balash, a brother of Peroz, to the throne.