William Wallace Kollar (born November 27, 1952) is an American football coach and former player. 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. Kollar has 34 years of coaching experience, including the last 28 seasons coaching defensive linemen in the NFL. Before coming to Denver in 2015, he coached the defensive line for Houston (2009-14), Buffalo (2006-08), St. Louis (2001-05) and Atlanta (1990-2000).