Great Salt Plains Lake is a reservoir located within the Salt Plains National Wildlife Refuge in Alfalfa County, Oklahoma in the United States named because of the salt flats in the area and for the Salt Fork Arkansas River, which is dammed to form the lake. It is notable for the variety of birds that are attracted to Ralstin Island and also for the selenite crystals that can be collected along the shoreline. Recent droughts, most notably that of 2011, have had an adverse effect on the future of the lake.

The Salt Plains National Wildlife Refuge is part of the United States system of national wildlife refuges. It is located in Alfalfa County in northern Oklahoma, north of Jet, along Great Salt Plains Lake, which is formed by a dam on the Salt Fork of the Arkansas River.