The Ladon (Ancient Greek and Katharevousa: Λάδων, Ládōn; Demotic Greek: Λάδωνας, Ládōnas) is a river in the Peloponnese peninsula of Greece. It features in Greek mythology. It is a tributary to the river Alfeios, which empties into the Ionian Sea. It is 70 km (43 mi) long.
The Ladon rises on the western slope of the Aroania mountain, near the village Kastriá, Kleitoria municipal unit, Achaea. It flows south, receives its left tributary Aroanios, flows along Kleitoria and turns southwest near the Arcadian border. It flows through the artificial Ladon Lake, and turns south again near Dimitra. It flows into the Alfeios 3 km southeast of the village Tripotamia.