The siege of Sestus (c.367-6 BC) saw forces loyal to the Persian emperor Artaxerxes II unsuccessful besiege allies of the rebel satrap Ariobarzanes, during the second stage of the Satrap's revolt.
The siege is mentioned in Xenophon's Agesilaus (II 26). Ariobarzanes, who was probably a usurper as satrap of Hellespontine Phrygia, had refused to hand his satrapy over to its rightful holder. Artaxerxes sent Autophradates, satrap of Lydia, Mausolus, satrap of Caria and Cotys, satrap of Paphlagonia and king of Thrace to deal with the revolt.
Mausolus commanded a fleet of 100 ships and blocked Ariobarzanes in either Assus or Adramyttium. Autophradates commanded the land army besieging Adramyttium, while Cotys besieged Sestus, which was on straits side of the Thracian Chersonese (the modern Gallipoli).
Ariobarzanes asked for help from Athens and from Sparta. Athens sent a force under Timotheus, but this withdrew when the Athenians discovered that Ariobarzanes was in revolt against Artaxerxes. Sparta sent King Agesilaus, a successful general in his time, but now getting quite elderly.
According to Xenophon Autophradates abandoned the siege when the Spartans appeared. Mausolus also withdrew, and this forced Cotys to abandon the siege of Sestus. Ariobarzanes retained his possessions, and went on to play a part in the third and most serious phase of the Satrap's Revolt.