Lake Grahovo (Montenegrin: Grahovsko jezero, Граховско језеро) is a lake in Nikšić municipality, near the town of Grahovo in southwestern Montenegro.
It is an artificial lake which is an accumulation of the Grahovo River. Bottom of the lake is mostly dolomite-based. The lake itself is 700 meters long, 200 meters wide and 25 meters deep. The dam is 30 metres high, and three meters wide. The lake is a significant water reservoir used for the agricultural production of Grahovo, but is also used for sport and recreation. Construction of the dam was initiated in 1952, finished in 1962, while it has undergone a reconstruction in 1988.