Thrasyllus (; ; died 406 BC) was an Athenian strategos (general) and statesman who rose to prominence in the later years of the Peloponnesian War. First appearing in Athenian politics in 410 BC, in the wake of the Athenian coup of 411 BC, he played a role in organizing democratic resistance in an Athenian fleet at Samos. There, he was elected strategos by the sailors and soldiers of the fleet, and held the position until he was controversially executed several years later after the Battle of Arginusae.