John Eudes O'Leary (19 August 1949 – 26 March 2020) was an Irish professional golfer who played on the European Tour through the 1970s and 1980s.

After retiring as a tournament golfer he was an active administrator, being a director of the European Tour from 1985 to 2019 and being on the Ryder Cup committee.

O'Leary was born in Dublin and joined Foxrock Golf Club, situated in the southern part of the city, as a junior member in the 1960s.

In December 1972 he took a three-shot lead entering the final round of the South African Masters after shooting a third-round 64 (−6).

Later in the season, at the Western Province Open, he once again held the lead entering the final round but shot a disappointing 75 (+2) to lose to South Africa's Hugh Baiocchi by one.

[4] Two seasons later, in February 1975, O'Leary finished in third place at the South African Open behind Gary Player.

[5] The next week he finally won, winning the Holiday Inns Royal Swazi Sun Open, an official event on the South African Tour which was played in Swaziland.

[6] Later in 1975, back in Europe, he picked up a runner-up finish at the Open de France, tying for second with fellow Irishman Eamonn Darcy and in May, playing with Jack Newton, he won the Sumrie-Bournemouth Better-Ball.