Duffey Lake Provincial Park, Provincial park in Squamish-Lillooet Regional District, Canada.

Duffey Lake Provincial Park covers 4,048 hectares in a narrow band along the south shore of Duffey Lake, widening on the north shore and reaching Mount Rohr, 2,438 metres high, at its western boundary. Highway 99 runs along the south shore and cuts through the park. The lake's inflow and outflow is Cayoosh Creek.

Duffey Lake Provincial Park was established on 14 June 1993. Long before that, the lake and the Cayoosh Creek valley formed a travel route between Lillooet Lake and the St'at'imc peoples toward the Fraser River, running along the lake's east shore. Archaeological work in 1999 found no artifacts, but the lake remains important in local oral tradition.

The lake and the Cayoosh Creek valley formed an early travel route between Lillooet Lake and the St'at'imc toward the Fraser River, following the lake's east shore. The lake features in the oral tradition of the surrounding First Nations; a 1999 archaeological survey found no artifacts. The park lies in the territories of the N'Quatqua and St'at'imc (Mt. Currie Indian Band), and the Sekw'elw'ás First Nation (formerly Cayoose Creek Indian Band) also held traditional use rights.

Visitors can reach the lake by using a gravel boat launch, but should bring their own drinking water as the park has no reliable potable water sources. Plan accordingly when organizing your visit.

Only about 5% of the park is set aside for recreation; the rest protects the leeward Pacific Ranges ecosystem. The lake's fish include bull trout, Dolly Varden and mountain whitefish, and the park spans four biogeoclimatic zones, from Interior Douglas-fir lowland to alpine tundra above roughly 1,700 m.