Stephen Christopher Spagnuolo (; born December 21, 1959) is an American football coach who is the defensive coordinator for the Kansas City Chiefs of the National Football League (NFL).
He rejoined Andy Reid's staff after being a defensive assistant with him from 1999-2006.
Spagnuolo went on to win a Super Bowl with the New York Giants as defensive coordinator.
Following two seasons in New York, He was the head coach of the St.
Louis Rams for 3 seasons, was an assistant with the Baltimore Ravens, had a one season stint with the New Orleans Saints, and then back with the Giants as defensive coordinator in 2015.
He was named interim head coach after the firing of former head coach Ben McAdoo on December 4, 2017.
Spagnuolo has also worked as a college football assistant coach for the University of Connecticut, the University of Maine, Lafayette College, Rutgers University, Bowling Green University, and the University of Massachusetts-Amherst.
He also spent time in the original World League of American Football and its successor, NFL Europe.