Jack Weyman Nelson (November 8, 1931 – November 5, 2014) was an American competition swimmer and swimming coach. Nelson represented the United States at the 1956 Summer Olympics in Melbourne, Australia, and competed in the men's 200-meter butterfly, finishing fourth in the event final. He later served as the head coach for the U.S. Olympic women's swim team at the 1976 Summer Olympics in Montreal, Quebec. Nelson was inducted into the International Swimming Hall of Fame as an "Honor Coach" in 1994, and the American Swimming Coaches Association Hall of Fame in 2009.