Oosthuizen is a South African surname, especially common among Afrikaners. Notable people with the name include:
Caylib Oosthuizen (born 1989), South African rugby union playerCoenie Oosthuizen (born 1989), South African rugby union playerD. C. S. Oosthuizen (born 1926; also known as Daantjie Oosthuizen), South African philosopherDevin Oosthuizen (born 1988), South African rugby union playerEtienne Oosthuizen (born 1992), South African rugby union playerEtienne Oosthuizen (born 1994), South African rugby union playerJohn Robert Oosthuizen (born 1987), South African javelin throwerLouis Oosthuizen (born 1982), South African professional golferNicolaas Oosthuizen (born 1996), South African rugby union playerOckie Oosthuizen (born 1955), South African rugby union playerTheo Oosthuizen (born 1964), South African rugby union player and coachThomas Oosthuizen (born 1989), South African professional boxerAlso:
Deon Oosthuysen (born 1963), South African rugby union player and coach