William Wallace "Bill" Kollar (born November 27, 1952) is an American football coach and former player. He is currently the defensive line coach for the Houston Texans of the National Football League (NFL), a position he has held since 2009. Kollar played as a defensive lineman in the NFL for the Cincinnati Bengals from 1974 to 1976, and the Tampa Bay Buccaneers from 1977 to 1981.