Pat Day is a retired professional American jockey. Day participated in rodeo events before beginning his jockey career in 1973 at Prescott Downs, a small racetrack in Arizona. He recorded his first major victory that year in the Jockey Club Gold Cup aboard longshot Great Contractor.

He is a four-time winner of the Eclipse Award for Outstanding Jockey. Day won nine Triple Crown races and 12 Breeders' Cup races. He was once the leader for career Breeders' Cup wins though he was later surpassed as the events were expanded after he retired. Pat Day retired in 2005 with 8,803 wins (ranked fourth all-time as of 2021) and as the all-time leading jockey in money earned (also as nof 2021). He was a dominant rider on the Kentucky riding circuit and holds all of the current (2021) career riding records at Churchill Downs and Keeneland. Day's signature wins include winning the inaugural $3 million Breeders' Cup Classic in 1984 aboard Wild Again and his partnership with Easy Goer in a rivalry with Sunday Silence.

Day was inducted into the National Museum of Racing and Hall of Fame in 1991 and the Arkansas Sports Hall of Fame in 1999. Day was a born-again christian, and was very active in the chaplain roles around the race tracks. In 2016, Kentucky Governor Bevin appointed Day to the Kentucky Horse Racing Commission.