Lake Minnewanka ("Water of the Spirits" in Nakota - the Stoney Indian language) is a glacial lake located in the eastern area of Banff National Park in Canada, about five kilometres (3.1 miles) northeast of the Banff townsite. The lake is 28 km (17 mi) long and 142 m (466 ft) deep, making it the longest lake in the mountain parks of the Canadian Rockies (the result of a power dam at the west end).

The lake is fed by the Cascade River, flowing east of Cascade Mountain, and runs south through Stewart Canyon as it empties into the western end of the lake. Numerous streams flowing down from Mount Inglismaldie, Mount Girouard and Mount Peechee on the south side of the lake also feed the lake.

Dams were built in 1912 and 1941 to supply the town with hydro-electric power. The most recent dam (1941) raised the lake 30 m (98 ft) and submerged the resort village of Minnewanka Landing that had been present there since 1888. Because of the presence of the submerged village, submerged bridge pilings, and submerged dam (the one from 1912) the lake is popular among recreational scuba divers.