Lake Towuti (Indonesian: Danau Towuti) is a lake in South Sulawesi, Indonesia. It is located at (2°45′0″S121°30′0″E). Surrounded by mountains, it is the largest lake of the island of Sulawesi and one of the five lakes of the Malili Lake system (the other being Matano, and the small Mahalona, Masapi and Lontoa (Wawantoa)). A river flows from the lake to the Boni Bay.