(6th century BC), king of Persia in 522–521 BC.

Bardiya was the son of Cyrus the Great of Persia. According to both the Greek historian Herodotus and the Persian king Darius (Darius I)'s account in his inscription at Bīsitūn, Bardiya was murdered by his brother, King Cambyses, but was later successfully impersonated by Gaumata, a Magian, who was able to seize the throne when Cambyses died in 522 BC. The usurper reigned for only eight months, however, before he was slain by Darius and other Persian nobles suspicious of his origin. Certain modern historians consider that Darius, who succeeded to the throne, invented the story of Gaumata to justify his actions and that the murdered king had indeed been a son of Cyrus.