Doctor John Colin Gregory (28 July 1903 – 10 January 1959) was an amateur British tennis player, best remembered for winning the Australian Open in 1929.

Like his father, he became a medical doctor but was also a successful amateur lawn tennis player in both doubles and singles.

[2] In the 1920s he played doubles with Ian Collins and they were runners up at the 1929 Wimbledon Championships.

[1] Following the Second World War, Gregory was captain of the British Davis Cup team.

[1] Gregory became chairman of the All-England Club at Wimbledon in 1955, where he died in 1959 in the changing rooms following a match.