|Location||La Tuque, Mauricie, Quebec|
|Primary outflows||Saint-Maurice River|
|Max. length||100 km (62 mi)|
|Max. width||48 km (30 mi)|
|Surface area||1,570 km2 (610 sq mi)|
|Average depth||5 m (16 ft)|
|Shore length1||5,650 km (3,510 mi)|
|Surface elevation||404 m (1,325 ft)|
|1 Shore length is not a well-defined measure.|
The Gouin Reservoir (in French: Réservoir Gouin) is a man-made lake in the central portion of the Canadian province of Quebec, fully within the boundaries of the City of La Tuque. It is not one contiguous body of water, but the collective name for a series of connected lakes separated by innumerable bays, peninsulas, and islands with highly irregular shapes. It has therefore a relative long shoreline of over 5,600 km (excluding islands) compared to its surface area of 1,570 km². It is the source of the Saint-Maurice River.
The reservoir is named after Jean Lomer Gouin, who was Premier of Quebec when, in 1918, the Shawinigan Water & Power Company impounded the reservoir for hydroelectric development. The Gouin Reservoir has a 600 mW station for local use, but is used to control the flow of the St-Maurice River for the stations down-stream (all operated now by Hydro-Québec).
There are no paved roads to the Gouin Reservoir, but it is accessible by several unpaved forest roads and by bush plane. The reservoir is a popular fishing destination with numerous commercial outfitters and private lodges along its shores.
Waterfowl present in the region include the American black duck (Anas rubripes), mallard (Anas platyrhynchos), green-winged teal (Anas crecca), ring-necked duck (Aythya collaris), common merganser (Mergus merganser), hooded merganser (Lophodytes cucullatus), common goldeneye (Bucephala clangula), bufflehead (Bucephala albeola), common loon (Gavia immer), Canada goose (Branta canadensis), bald eagle (Haliaeetus leucocephalus).