St. Clair Balfour III OC DSC (April 30, 1910 – May 9, 2002) was a Canadian businessman.

Born in Hamilton, Ontario, the son of St. Clair Balfour II and Ethel May Southam (the daughter of William Southam, the founder of Southam Newspapers), he attended Trinity College School in Port Hope, Ontario and he received a Bachelor of Arts degree from the University of Trinity College in 1931.

He then started working for The Hamilton Spectator, a Southam newspaper.

During World War II, he served in the Royal Canadian Navy in the North Atlantic and was awarded a Distinguished Service Cross.

In 1954, he was appointed executive vice-president and managing director of the Southam company.