Simon John Arthur Youl (born 1 July 1965) is a former professional tennis player from Australia.
Youl was an Australian Institute of Sport scholarship holder from 1981 to 1984.
As a junior player, Youl formed a successful doubles partnership with his fellow Australian player Mark Kratzmann. In 1983, the pair won the Boys' Doubles titles at the French Open, Wimbledon and the US Open. In singles, he reached three slam finals, attaining a ranking as high as No. 5 in the junior world rankings in 1983.
As a professional player, Youl won two top-level singles titles (at Schenectady in 1989, and Singapore in 1992), and two tour doubles titles (Casablanca in 1990, and Bucharest in 1994). His best singles performances at Grand Slam events came in reaching the fourth round at Wimbledon in 1988 (lost to Stefan Edberg) and the Australian Open in 1990 (lost to Ivan Lendl).
Youl's career-high rankings were world No. 80 in singles and world No. 63 in doubles (both in 1992).
He retired from the professional tour in 1994 (playing one Challenger event the following year). Since retiring as a player, he has worked as a tennis coach in Hobart, Tasmania.