John Robert Oosthuizen (born 23 January 1987) is a South African javelin thrower.

He is a second generation athlete following in his father Johan Oosthuizen's footstep.

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.

This biographical article relating to South African athletics is a stub.