British Columbia Southern Interior (formerly known as Southern Interior, Kootenay—Boundary—Okanagan and West Kootenay—Okanagan) was a federal electoral district in the province of British Columbia, Canada, that had been represented in the House of Commons of Canada from 1997 to 2015.

Regions included in the riding are the Similkameen, the southern half of the South Okanagan region, the Boundary Country, all of the West Kootenay region, the Slocan Valley, Lower (but not Upper) Arrow Lake, and including the east shore of Kootenay Lake from opposite Kaslo northwards.

Municipalities within the riding are Princeton, Keremeos, Oliver, Osoyoos, Greenwood, Grand Forks, Trail, Rossland, Warfield, Montrose, Fruitvale, Castlegar, Nelson, Salmo, Slocan, New Denver, Silverton, and Kaslo.

In the 2003 redistribution, the riding was replaced by the new riding of Southern Interior, with a small part being redistributed into Kootenay—Columbia and a small part added from Okanagan—Coquihalla.

In 2004, its name was changed to "British Columbia Southern Interior".