İzmir Province (Turkish: İzmir ili) is a province and metropolitan municipality of Turkey in western Anatolia, situated along the Aegean coast. Its capital is the city of İzmir, which is in itself composed of the province's central 11 districts out of 30 in total. To the west, it is surrounded by the Aegean Sea, and it encloses the Gulf of Izmir. Its area is 11,891 square kilometres (4,591 square miles), and its population is 4,462,056 (2022). Neighboring provinces are Balıkesir to the north, Manisa to the east, and Aydın to the south. The traffic code of the province is 35.
Major rivers of the province include the Küçük Menderes river, Koca Çay (with Güzelhisar dam), and Bakırçay.