David Leedom Helliwell (July 26, 1935 – 1993) was a Canadian rower who competed in the 1956 Summer Olympics.
He won a silver medal in a coxed eight alongside Philip Kueber, Richard McClure, Douglas McDonald, Bill McKerlich, Carlton Ogawa, Donald Pretty, Lawrence West, and Robert Wilson.
He also won a silver medal in the 1958 Commonwealth Games in Australia but this time in a coxed four.