Robert Allen Ryan (born December 13, 1962) is an American football coach who is currently the senior defensive assistant for the Las Vegas Raiders of the National Football League (NFL). Ryan has served as a defensive coordinator or assistant coach for seven different NFL teams. He was the linebackers coach for the New England Patriots when they won both Super Bowl XXXVI and Super Bowl XXXVIII. Ryan is the son of Buddy Ryan and the twin brother of Rex Ryan.