The 1921 Centre vs. Harvard football game was a regular-season college football game played on October 29, 1921, at Harvard Stadium in Allston, Massachusetts. The contest featured the undefeated Centre Praying Colonels, representing Centre College, and the undefeated Harvard Crimson, representing Harvard University. In a rematch of a game played between the two teams the year prior, Centre defeated Harvard in what is widely considered one of the greatest upsets in college football history.