Justin Karn (born June 16, 1981) is a Canadian judoka who represented Canada in Judo at the 2012 Paralympics in the -60 kg category.
He was eliminated from the tournament in repêchage due to disqualification by penalties (four shido leading to hansoku make) in his match against South Korea's Min-Jae Lee.
Karn has been competing in Judo for around 18 years, and in 2011 won bronze in the -60 kg category of the Parapan American Games.
He was born with aniridia, an eye condition that left him without irises, and also has astigmatism and mutated corneas in both eyes.