The Ionian Revolt, and associated revolts in Aeolis, Doris, Cyprus and Caria, were military rebellions by several Greek regions of Asia Minor against Persian rule, lasting from 499 BCE to 493 BCE. At the heart of the rebellion was the dissatisfaction of the Greek cities of Asia Minor with the tyrants appointed by Persia to rule them, along with the individual actions of two Milesian tyrants, Histiaeus and Aristagoras. The cities of Ionia had been conquered by Persia around 540 BCE, and thereafter were ruled by native tyrants, nominated by the Persian satrap in Sardis. In 499 BCE, the tyrant of Miletus, Aristagoras, launched a joint expedition with the Persian satrap Artaphernes to conquer Naxos, in an attempt to bolster his position. The mission was a debacle, and sensing his imminent removal as tyrant, Aristagoras chose to incite the whole of Ionia into rebellion against the Persian king Darius the Great.

The Ionian Revolt constituted the first major conflict between Greece and the Persian Empire, and as such represents the first phase of the Greco-Persian Wars. Although Asia Minor had been brought back into the Persian fold, Darius vowed to punish Athens and Eretria for their support of the revolt. Moreover, seeing that the myriad city states of Greece posed a continued threat to the stability of his Empire, according to Herodotus, Darius decided to conquer the whole of Greece. In 492 BCE, the first Persian invasion of Greece, the next phase of the Greco-Persian Wars, began as a direct consequence of the Ionian Revolt.