John Alfred Thomas Horn (6 November 1931 – 26 August 2001[1]) was a British tennis player, and he won the Wimbledon Boys' singles Championship in 1950.

His first title was as an eighteen-year-old, at the Derbyshire championships in Buxton, when he beat George Godsell in the final.

His last amateur title was in 1956 at the North of England Hardcourts, beating Michael Hann in the final.

Horn turned professional in the late 1950s and in 1967 he won the British Pro Championships held at Eastbourne with a victory over Charles Applewhaite.

[5] Horn's best result at a Grand Slam events was reaching the third round at the 1952 Wimbledon Championships, before losing to Budge Patty.