Tragilos (Greek: Τράγιλος, Greek pronunciation: [ˈtraʝilos]) is a village and a former municipality in the Serres regional unit, Greece. Since the 2011 local government reform it is part of the municipality Visaltia, of which it is a municipal unit. The municipal unit has an area of 197.758 km. Population 3,104 (2021). The seat of the municipality was in Mavrothalassa.