Julian Letterlough (December 25, 1969 – July 8, 2005) was an American professional boxer from Harrisburg, Pennsylvania. Known as "Mr. KO", Letterlough was boxer who was often featured on ESPN.
Letterlough became a professional boxer in 1998 at the late age of 28 after a seven-year stint in prison for assault. He fought as a light heavyweight and was unbeaten in his first 16 fights.
He fought against Julio César González in 2001, a fight in which González was down three times, and Letterlough down twice. González won by decision. Later that year, he got a shot at International Boxing Federationcruiserweight titleholder Vassiliy Jirov, but lost in the 8th round by TKO. He lost a decision later that year to David Telesco, and in 2003 was knocked out by Richard Hall. In 2004 he fought a draw against Daniel Judah, a fight in which Judah went down in round five and was docked a point for holding in round seven.