Tony Steven Casillas (born October 26, 1963) is a retired American football defensive lineman in the National Football League from 1986 through 1997. While at the University of Oklahoma he helped win the 1985 NCAA National Championship. He also won the Lombardi Award in 1985 and was the 1985 UPI Lineman of the Year. Casillas was also part of the Dallas Cowboys back to back victories in Super Bowl XXVII and XXVIII. In 2004 he was inducted into the College Football Hall of Fame.