Nea Filadelfeia is a suburban town in the Athens agglomeration, Greece. Since the 2011 local government reform it is part of the municipality Nea Filadelfeia-Nea Chalkidona of Central Athens regional unit, of which it is the seat and a municipal unit. The municipal unit has an area of 2.850 km2. It was named after the Anatolian city Filadelfeia, now Alaşehir in Turkey, and it was settled by Greek refugees from Asia Minor after the Greco-Turkish War (1919-1922).

Alaşehir is a municipality and district of Manisa Province, Turkey. Its area is 971 km2, and its population is 104,717 (2022). It is situated in the valley of the Kuzuçay, at the foot of the Bozdağ Mountain. The town is connected to İzmir by a 105 km (65 mi) railway.