The Robert-Bourassa Reservoir () is a man-made lake in northern Quebec, Canada. It was created in the mid-1970s as part of the James Bay Project and provides the needed water for the Robert-Bourassa and La Grande-2-A generating stations. It has a maximum surface area of , and a surface elevation between and . The reservoir has an estimated volume of , of which is available for hydro-electric power generation.
The reservoir is formed behind the Robert-Bourassa Dam that was built across a valley of the La Grande River. This dam was constructed from 1974 to 1978, is 550 m (1,800 ft) wide at its base, and has 23 million m<sup>3</sup> (30 million yd<sup>3</sup>) of fill. There are another 31 smaller dikes keeping the water inside the reservoir.