William Frederick Truax III was an American professional football player who was a tight end in the National Football League (NFL) for the Los Angeles Rams and Dallas Cowboys. He played college football for the Louisiana State University (LSU) Tigers. Truax was among the earliest tight ends during the 1960s to play in the style established by such tight ends as John Mackey, Mike Ditka, and Ron Kramer in being equally talented as pass receivers and powerful blockers. During Truax's prime years as a starter, his teams had a combined record of 60–20–4, went to the playoffs three times, and won Super Bowl VI. In the Cowboys' 1971 Super Bowl winning season, Truax was part of coach Tom Landry's offensive play calling system where Landry would alternate Truax and Ditka at tight end after every play to bring Landry's offensive play instructions to the Cowboys quarterback.