Sir William James Gage (September 16, 1849 – January 14, 1921) was a Canadian educator, entrepreneur and philanthropist.

The company mainly specialized in textbooks but also sold writing paper and envelopes.

Gage was one of the founders of the National Sanitarium Association and established several treatment facilities to combat tuberculosis.

He helped form the Ontario Associated Boards of Trade and served as its first president.

He was head of a group that opposed street car service on Sundays.