Marcus Dell Gastineau (born November 20, 1956) is a former American football player who was a leading defensive end for the New York Jets from 1979 to 1988. A five-time Pro Bowler, his 107½ quarterback sacks in only his first 100 starts in the NFL made him one of the quickest and most feared pass rushers of his generation. Gastineau is ranked the 8th greatest pass rusher in NFL History on NFL Network's NFL Top 10 Pass Rushers.

Gastineau was among the most talented and honored defensive linemen of his era. He made the Pro Bowl five straight seasons (1981–85) and finished his ten-year career with 107½ sacks, the Jets all-time record. He was a First-team All-Pro in years 1981-85 and was consensus All-AFC in each of those years.