Petra Rivers (born 11 December 1952) is a retired Australian athlete who specialised in the javelin throw.

Still only seventeen, it was her fourth national junior javelin championship win.

Her performances earned her a place in the Australian team for the 1970 Commonwealth Games where she comfortably won the gold medal in Edinburgh.

In late 1971, she threw Australian and World Junior records of 61.76 and 62.24 metres, in quick succession but injury kept her out of the 1972 national titles and Olympic Games.

She recovered to repeat her Commonwealth Games gold medal win in Auckland but continuing injuries forced her retirement from the sport, at age 22, in 1975.