Phlius (//; Ancient Greek: Φλειοῦς, Phleious) was a Greek city in the northwestern Argolid (now in modern Corinthia, near Nemea), in the Peloponnese, said to be named after the Greek hero Phlias but formerly called Araethyrea (//; Ἀραιθυρέα, Araithurea).
Like many other cities of ancient Greece, Phlius fell into civil strife between a democratic and an oligarchic faction during the 4th century BCE; the democratic faction initially gained control and exiled its opponents, but in 380 BCE a Spartan army under Agesilaus laid siege to the city for some twenty months, eventually forcing the Phliasians to capitulate and accept oligarchic government.
- Stephanus of Byzantium s. v. Phlious.
- Fine, p. 559.
- Fine, John V.A. The Ancient Greeks: A critical history (Harvard University Press, 1983) ISBN 0-674-03314-0
- Xenophon (1890s) [original 4th century BC]. Hellenica. Trans. Henry Graham Dakyns. Wikisource.