John Robert Oosthuizen (born 23 January 1987) is a South Africanjavelin thrower. He is a second generation athlete following in his father Johan Oosthuizen's footstep. Oosthuizen senior's, who never got the chance to represent his country in international competition, biggest achievement is a throw of 80.92 metres, which he achieved in 1990.
Oosthuizen junior's personal best throw is 86.80 metres which he achieved at the Yellow Pages meeting in Oudsthoorn on 1 March 2008. The throw was better than his 84.52 metres, achieved at the 2007 World Championships in Osaka and helped him to qualify for the 2008 Olympic Games in Beijing.