Marvin Alex Dunphy (born 1948) is an American former volleyball player and head coach.

[3] He also led the United States men's national volleyball team to the gold medal in the 1988 Summer Olympics.

[2][5] From 1985 to 1988, Dunphy was the head coach of the United States men's national volleyball team.

[4][8] In 1988, Dunphy was the recipient of the Coach of the Year Award from the Fédération Internationale de Volleyball (FIVB).

[11] Dunphy is a Professor Emeritus of Sports Medicine in the Natural Science Division at Pepperdine Seaver College.