Histiaeus was the tyrant of Miletus under Persian suzerainty in the late 6th century BCE. After serving King Darius I, he was detained at the Persian court in Susa. He secretly encouraged the Ionian Revolt in an attempt to engineer his release, but upon returning, he was distrusted by both the Ionians and the Persians.

Following failed attempts to regain power and a period of piratical activities, he was captured and executed by the Persians. No literary works by Histiaeus are attested. Herodotus, the primary source for his life, portrays him solely as a political actor.

Histiaeus is a significant figure for his role in instigating the Ionian Revolt, a major prelude to the Greco-Persian Wars. His actions illustrate the complex dynamics of ambition and loyalty among Greek client rulers within the Persian Empire, highlighting their precarious political position.