William James Mallon (born February 2, 1952) is an American orthopedic surgeon, former professional golfer and a leading authority on the history of the Olympic Games.

After leaving the PGA Tour, Mallon returned to Duke University to study medicine graduating as an M.D.

He was a resident at Duke University medical center between 1984 and 1990 and is now the Associate Consulting Professor of Orthopaedics as well as having his own practice.

Mallon specializes in complex reconstructive shoulder and elbow surgery and is a fellow of the American Academy of Orthopaedic Surgeons, a member of the American Shoulder and Elbow Surgeons, where he served as vice-president in 2012 and will be president in 2014, and a member of the advisory council of the Institute of Preventative Sports Medicine.

Mallon is also a leading authority on the history of the Olympic Games and has written 24 books on the subject.