Jacobus Petrus "Os" du Randt (born 8 September 1972) is a South African former rugby union player. A loosehead prop, he retired as the most-capped forward in the history of the South Africa national team, and won two Rugby World Cups, in 1995 and 2007. He ended his career as one of the last remaining international players from the amateur era of the sport and the last active member of the 1995 World Cup-winning squad. His final match was the 2007 Rugby World Cup final, which the Springboks won, with Du Randt playing the entire 80 minutes. He is one of 43 players who have won the Rugby World Cup on multiple occasions.
For most of his career, he played in the Currie Cup for the Free State Cheetahs, though he spent one season with the Blue Bulls. In Super Rugby, he represented the Free State Cheetahs, the Cats, the Bulls and the Cheetahs.
Du Randt is nicknamed Os, meaning "ox" in Afrikaans, due to his large size and powerful scrummaging.