Osoyoos Lake is a lake located in British Columbia and Washington. Osoyoos is derived from the word sẁiẁs meaning "narrowing of the waters" in the local Okanagan language .
Located on the lakeshore are the towns of Osoyoos, British Columbia and Oroville, Washington. The lake's maximum elevation is 912.78ft, while its minimum elevation is 909.46ft. The 62-year average discharge into the Okanogan River at Oroville is 683cuft/s. Maximum discharge in 2004 was 1340cuft/s. Oroville's Osoyoos Lake State Park is located on its shore.