Charidemus (in Greek Χαρίδημος), of Oreus in Euboea, was a Greek mercenary leader of the 4th century BC. About 367 BC, he fought under the Athenian general Iphicrates against Amphipolis. Being ordered by Iphicrates to take the Amphipolitan hostages to Athens, he allowed them to return to their own people, and joined Cotys, king of Thrace, against Athens.