Mary Grigson (born 3 June 1971) is an Australian cross-country mountain biker.
Grigson participated in the 1996 Summer Olympics in Atlanta coming 15th in the women's Cross-country event. She also competed in the women's Cross-country event at the 2000 Summer Olympics in Sydney where she came 6th.
She won a bronze medal at the 2002 Commonwealth Games in the cross-country event.
She was inducted into the Cycling Australia Hall of Fame in 2016.