Derek James Clayton (born 17 November 1942) is a former Australian long-distance runner, born in Cumbria, England and raised in Northern Ireland.
Clayton represented Australia at the 1968 Summer Olympics in Mexico City, finishing in 7th place (2:27:23).
At the 1971 Australian Athletics Championships, he won the marathon in 2:11:08.8.
Two years later, in 1973, he won the Australian Athletics Championships marathon again in 2:12:07.6.
[3] Clayton was inducted into the Sport Australia Hall of Fame in 1999.