Agios Konstantinos is a village in Sparta Municipality, in the regional unit of Laconia Prefecture, in the region of Peloponnese, Greece. Agios Konstantinos lies in the Taygetus mountains, on the Peloponnese peninsula. It has 55 inhabitants (2021). The nearest city is Kalamata, 25 km to the southwest. Among the landmarks around are Mystras (18.0 km), Sparta (21 km) and Messene (32 km). Among the natural features are Cave of Caiada (14.9 km).

Also written Άγιος Κωνσταντίνος.