Jason Lunn (born September 19, 1974 in Boulder, Colorado) is a retired American middle-distance runner who mostly competed in the 1500 meters. He was the US outdoor champion at 1500m in 2003. He represented his country at one outdoor and three indoor World Championships. He earned All-American honors for Stanford University in cross country in 1997, and multiple times in track and field. He is now an assistant professor at Penn State University.