John Colin Lumley (born August 7, 1992) is a British professional real tennis player currently ranked at number 2 in the world.

He unsuccessfully challenged Camden Riviere for the 2023 Real Tennis World Championship at Westwood Country Club in Vienna, Virginia.

Shortly afterwards, he recorded his so-far only win against then-future World Champion Camden Riviere at the USCTA National League.

He won two-second-tier tournaments in 2015, the Satellite draw of the US Pro Singles against Women's World Champion Claire Fahey, as well as the US National at Tuxedo.

However, a quarter final loss against Ben Taylor-Matthews at the 2019 British Open meant that he failed to qualify for the 2020 Real Tennis World Championship.

[5] The 2020 season started well for Lumley, winning the Governor's Cup in Hobart against Chris Chapman and reaching the semi-final at the Australian Open.

Lumley partnered with Steve Virgona at the 2022 World Doubles Championship in Bordeaux, reaching the final against Riviere and Tim Chisholm.

[10] In the second round, Lumley played against Nick Howell, also at the Racquet Club of Philadelphia, winning 7 sets to 1 and qualifying to challenge Camden Riviere for the World Championship.

[13] He again partnered Steve Virgona at the World Doubles Championships in Chicago, in a rematch of the previous edition against Riviere and Chisholm, but lost 5 sets to 2.