King T. Leatherbury (born March 26, 1933 in Shady Side, Maryland) is an American Thoroughbred racehorse trainer who ranks fifth all-time in wins among U.S. trainers. Called a Maryland racing legend by Churchill Downs, King T. Leatherbury, along with John J. Tammaro, Jr., Richard E. Dutrow, Sr. and Hall of Fame inductee Bud Delp, were known as Maryland racing's "Big Four". They dominated racing in Maryland during the 1960s and 1970s and helped modernize flat racing training.