Mark Williams (born 27 March 1979) is an Australian-born American volleyball and beach volleyball player. Williams was born in Sydney but moved to the United States when he was nine years old. In 1999, while he was at UCLA, Williams trained with the Australian national indoor team. At the 2000 Summer Olympics in Sydney, was a libero of the squad which placed eighth among 12 participating teams. In 1998 he made his debut in beach volleyball with where they competed in Hermosa Beach. After graduating in 2001, he played in five AVP events that year with several partners.