Euthydemus () may refer to:
People
- Euthydemus, a fleet commander for Athens during the Sicilian Expedition, 415 to 413 BC
- Euthydemus of Chios, a 5th-century sophist who features in Plato's Euthydemus
- Euthydemus, a son of Cephalus, mentioned in Plato's Republic
- Euthydemus, a son of Diocles, mentioned in Xenophon's Memorabilia
- Euthydemus I (3rd century BC), ruler of the Greco-Bactrian Kingdom
- Euthydemus II (2nd century BC), ruler of the Greco-Bactrian Kingdom
- Euthydemus (tyrant) (3rd century BC), tyrant of Sicyon
Dialogues