Amos Alonzo Stagg (August 16, 1862 – March 17, 1965) was an American collegiate coach in multiple sports, primarily football, and an overall athletic pioneer. He was born in West Orange, New Jersey, and attended Phillips Exeter Academy. Playing at Yale, where he was a divinity student, and a member of the Psi Upsilon fraternity and the secret Skull and Bones society, he was an end on the first All-America team, selected in 1889.

He was elected to the College Football Hall of Fame as both a player and a coach in the charter class of 1951 and was the only individual honored in both areas until the 1990s. Influential in other sports, he developed basketball as a five-player sport and was elected to the Basketball Hall of Fame in its first group of inductees in 1959. A pitcher on his college baseball team, he declined an opportunity to play professional baseball but nonetheless influenced the game through his invention of the batting cage. He went on to earn an MPE from the Young Men's Christian Training School now know as Springfield College.

On March 11, 1892, Stagg, still an instructor at the YMCA School, played in the first public game of basketball at the Springfield (Mass.) YMCA. A crowd of 200 watched as the student team crushed the faculty, 5-1. Stagg scored the only basket for the losing side.