| Birth Place: | Port Augusta, South Australia |
| Height: | 180 cm |
| Weight: | 70 kg |
| Sport: | Athletics |
| Event: | Mile-10,000 m, steeplechase |
| Pb: | 5000 m – 13:37.2 (1970) 10,000 m – 28:43.6 (1969) 3000 mS – 8:21.98 (1970)[1] [2] [3] |
| Club: | UTEP Miners, El Paso |
| Show-Medals: | yes |
Kerry Dennis O'Brien (born 17 April 1946) is a retired Australian runner. Competing in the steeplechase he won a silver medal at the 1966 British Empire and Commonwealth Games and finished fourth at the 1968 Summer Olympics. He held the world record in this event between 1970 and 1972. At the 1970 Commonwealth Games, O'Brien fell at the penultimate water-jump, while leading, and failed to finish the race. He also fell during the 1972 Olympics. He retired in 1973 having won nine Australian titles in the steeplechase, 5000 m and cross-country running.[4]
| 1966 | British Empire and Commonwealth Games | Kingston, Jamaica | 8th | 1 mile | |
| 2nd | 3000 m steeplechase | ||||
| 1968 | Olympic Games | Mexico City, Mexico | 4th | 3000 m steeplechase | |
| 1969 | Pacific Conference Games | Tokyo, Japan | 1st | 3000 m steeplechase | |
| 1970 | British Commonwealth Games | Edinburgh, Scotland | 8th | 10,000 m | |
| DNF | 3000 m steeplechase | ||||
| 1972 | Olympic Games | Munich, West Germany | DNF | 3000 m steeplechase | |
| 1973 | Pacific Conference Games | Toronto, Canada | 1st | 3000 m steeplechase |