Archidamus III, the son of Agesilaus II, was king of Sparta from 360 BC to 338 BC.

In 343 BC, the Spartan colony Tarentum asked for Sparta's help in the war against the Italic populations. In 342 BC Archidamus arrives in Italy, with a fleet and an army, and fights against the barbarians, but in 338 BC he is defeated and killed under the walls of Manduria.