Donald Graham Smith (born May 9, 1958) is a Canadian former competition swimmer who won a silver medal in the men's 4x100-metre medley relay at the 1976 Summer Olympics in Montreal, Quebec. He did so alongside teammates Stephen Pickell, Clay Evans and Gary MacDonald. His brother George and sister Becky also competed in swimming. He also won an NCAA national swimming championship at the University of California, Berkeley. Smith was inducted into the Alberta Sports Hall of Fame and Museum in 1978.