Kerry O'Brien (born 17 April 1946) is a former track and field athlete from Australia, who competed in the middle-distance running events. He was born in Port Augusta, South Australia. He represented his native country at two consecutive Commonwealth Games from 1966 and two Summer Olympics from 1968.
O'Brien was the world record holder in the men's 3,000 metres steeplechase for more than two years (1970–1972), setting a time of 8:21.98 at Berlin on 4 July 1970. At the 1970 Commonwealth Games, O'Brien fell at the final water-jump, while leading, and failed to finish the race. He also fell during the 1972 Olympics. He retired in 1973 with a total of nine Australian Championships to his credit. He won one cross country title, one 5000 metres title and seven steeplechase championships.