Ismenias (Ancient Greek: Ἰσμηνίας) was an ancient Theban politician of the 4th century BC. He rose to power in the years after the Peloponnesian War and pursued an anti-Spartan policy, which included harboring exiles fleeing the Thirty Tyrants in Athens. During a Spartan occupation of Thebes, he is identified, with Androcleides, as one of the leaders of the anti-Spartan faction and imprisoned. Plato names him as an example of someone who made a great amount of money in a short period of time, and includes him in a list of rich and powerful men with little moral fiber.
- Xenophon, Hellenica V.2.31
- Plato. Meno, 90a.
- Plato. Republic, 336a.
- Buck, Robert J. Thrasybulus and the Athenian Democracy: The Life of an Athenian Statesman. Franz Steiner Verlag, 1998, ISBN 3-515-07221-7