The Nisqually River (nuh-SKWAH-lee) is a river in west central Washington in the United States, approximately 81 mi (130 km) long. It drains part of the Cascade Range southwest of Tacoma, including the southern slope of Mount Rainier, into the southern end of Puget Sound.

It rises in southern Mount Rainier National Park, fed by the Nisqually Glacier on the southern side of Mt. Rainer. It flows west along the Pierce-Lewis county line, then northwest through the foothills, forming the boundary between Pierce and Thurston counties. It traverses the Nisqually Indian Reservation in its lower 10 mi (16 km) and enters Puget Sound approximately 15 mi (24 km) ENE of Olympia.

It is impounded for hydroelectricity by the Alder Dam , completed in 1944, and the La Grande Dam , completed in 1945.