John Ivor Disley CBE (20 November 1928 – 8 February 2016) was a Welsh athlete. He competed mainly in the 3000 metres steeplechase before co-founding the London Marathon and becoming active in sports promotion and administration. He was born in Corris, a village in Gwynedd and attended Oswestry Boys High School in Oswestry before studying at Loughborough College.
He competed for Great Britain in the 1952 Summer Olympics held in Helsinki in the 3000 metres steeplechase where he won the bronze medal. He set five British records in the steeplechase and four at two miles. He also set Welsh records at six different distances. He also broke the record for the traverse of the Welsh 3000 foot peaks.
He represented Wales twice at the Commonwealth Games, competing in 1954 and 1958, but did not win a medal either time. Disley's job was teaching PE at Isleworth Grammar School in south-west London.
Disley was one of the founders of the London Marathon, first held in 1981, after running the New York Marathon in 1979 and being very impressed by its success. He was president of the London Marathon Charitable Trust. Disley became vice-chairman of the UK Sports Council in 1974, a post he held until 1982. He was the leading pioneer of orienteering in the UK.
He was a member of the Welsh Sports Hall of Fame and was President of the Snowdonia Society.