John Joseph McMahon (December 3, 1928 – June 11, 1989) was an American professional basketball player and coach.

A 6'1" guard from St. John's University, McMahon was selected by the Rochester Royals in the 1952 NBA draft.

He played eight seasons in the National Basketball Association (NBA), for Rochester and the St. Louis Hawks.

McMahon became a successful coach in the American Basketball League,[1] the NBA and the American Basketball Association (ABA), with eleven seasons as a head coach in the three leagues.

He would also coach the Cincinnati Royals, the San Diego Rockets, and the ABA's Pittsburgh Condors.