Donald Graham Smith (born May 9, 1958) is a Canadian former competition swimmer who swam for the University of California Berkeley, and won a silver medal in the men's 4x100-metre medley relay at the 1976 Summer Olympics in Montreal, Quebec.

Smith attended the University of California Berkeley where he swam under Hall of Fame Coach Nort Thornton.

[1][2] At the 1978 Commonwealth Games in Edmonton, Alberta, he became the first competitor to win six gold medals at a single Commonwealth Games; he won the 100- and 200-metre breaststroke, 200- and 400-metre individual medleys, and was part of the winning 4x100-metre freestyle and 4x100-metre medley relay teams.

Taking off a year from college to train for the 1980 Summer Olympics, he lost his chance to participate when the games were boycotted by Canada.

Though he had been considered Canada's greatest swimmer, in 1982 he formally left competitive swimming, and served as a coach for several years before earning an MBA from St. Mary’s College of California.