Leonidio (Greek: Λεωνίδιο) is a town and a former municipality in Arcadia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality South Kynouria, of which it is a municipal unit. The town of Leonidio, with a population of 3.826, emerges from a spectacular landscape, bound by two abrupt mountainsides enclosing the town from the north and south.
The River Dafnon passes through the town, and its banks are linked with three bridges. The town is capital of the Tsakonia region, notable for its cultural and linguistic particularities, and the settlement itself offers striking and picturesque architecture; now a protected architectural site, there are very strict regulations for building within the town’s limits.