John Peter Olszewski (December 21, 1929 – December 8, 1996) was an American football fullback. He was drafted in the first round (fourth overall) of the 1953 NFL Draft and played professionally for the Chicago Cardinals, Washington Redskins and Detroit Lions. Olszewski was selected to play in the Pro Bowl after the 1953 and 1955 seasons. Known as Johnny O, he was among the first NFL players to wear the jersey number zero. He concluded his career in the American Football League (AFL) with the Denver Broncos in 1962.