Stephanus ("Fanie") Johannes du Plessis (born 23 February 1930 in Lichtenburg, North West – died 13 August 2001 in Pretoria, Gauteng) was a discus thrower and shot putter, who represented South Africa at two Summer Olympics in 1956 and 1960. He was twice gold medalist at the Commonwealth Games (in 1954 and 1958, then known as the British Empire and Commonwealth Games) in the men's discus throw event.