Leslie G. Cliff, OC (born March 11, 1955) is a Canadian former swimmer who competed at the 1970 British Commonwealth Games and won two gold medals at the 1974 Commonwealth Games.
She was born in Vancouver, British Columbia, where she attended York House School. As a 17-year-old, she won the silver medal in the 400-metre individual medley at the 1972 Summer Olympics in Munich, Germany.
In 1971, Cliff was made an Officer of the Order of Canada. She was inducted into the BC Sports Hall of Fame in 1976, Canada's Sports Hall of Fame in 1984, and the Canadian Olympic Hall of Fame in 1997.