Frederik Christoffel Hendrik "Frik" du Preez (born 28 November 1935) is a former South African rugby union player who represented Northern Transvaal and the Springboks. He was born on a farm near Rustenburg and went to school at in Parys (Orange Free State). Du Preez mostly played in the flank or lock positions. Du Preez made his test debut for the Springboks on 7 January 1961 in the flank position against England at Twickenham. He played his last test on 7 August 1971 at the age of 35 as a lock against Australia at the Sydney Cricket Ground.