The Sinanishko Lake (Bulgarian: Синанишко езеро) is a lake in Pirin, southwestern Bulgaria, situated below the Sinanitsa Peak in the small Sinanitsa Cirque at an altitude of 2,181 metres. With depth of 11.5 metres it is among the 10 deepest lakes in the mountain range. It has an elongated shape (175 x 80 m) and an area of 10,100 square metres.