Agios Konstantinos is a village in East Samos Municipality, in the regional unit of Samos, in the region of North Aegean, Greece. Agios Konstantinos lies in the Samos mountains, on the island of Samos. It has 318 inhabitants (2021). The nearest city is Chios, 87 km to the northwest. Near the border: Türkiye, 22 km. Beaches nearby: Platana (0.4 km), Kampos Vourliotes Beach (2.1 km), Tsabou (3 km). Among the landmarks around are Heraion of Samos (15.9 km), Pythagoreion (16.7 km) and Tunnel of Eupalinos (15.7 km). Among the natural features are Samiopoula (20 km) and Cave of Pythagoras (16.7 km).

Also written Άγιος Κωνσταντίνος.