John Arthur "Chubby" Cox III (born December 29, 1955 in Philadelphia, Pennsylvania), is a retired American professional basketball player.

A 6'2" guard, Cox attended Roxborough High School in Philadelphia. Cox played two years at Villanova University, and then starred at the University of San Francisco (USF), where he still ranks among the top 10 in single-season assists.

He was drafted in the 8th round (7th pick) by the NBA's Chicago Bulls in 1978. However, Cox did not make an NBA roster until the 1982-83 season, when he played seven games for the Washington Bullets, scoring 29 total points.

Cox played professionally in the Continental Basketball Association (CBA) from 1978-1981. Over three seasons with the Philadelphia Kings, Pennsylvania Barons, and Wilkes-Barre Barons, Cox averaged nearly 22 points per game. He scored 50 points in a December 28, 1979, game against the Lancaster Red Roses.

Cox married his girlfriend and former USF cheerleader Victoria and together they have a son, John Cox IV (born July 6, 1981). Cox IV followed his dad's footsteps by attending and playing college basketball for USF.