Harry William Bain, OC (1921 – December 21, 2001 ) was a Canadian pediatrician. He was raised in Cache Bay, Ontario, and graduated from the University of Toronto in 1944. He was a paediatrician at Toronto's Hospital for Sick Children from 1951 to 1985. From 1966 to 1976, he was the Paediatrician-in-Chief of the Hospital for Sick Children and the University of Toronto's Department Chairman of Paediatrics.