Theodore F. Chamberlain (July 6, 1838 – March 5, 1927) was an Ontario physician, businessman and political figure.

He was born in Smith's Mills, Upper Canada (later Harlem, Ontario) in 1838, the son of Dr. Asher Augustus Chamberlain who was also the local postmaster.

Chamberlain studied dentistry in Ottawa and practiced in Leeds County and then in New York state.

He also ran a drug store and served as the village's officer of health and as coroner for Stormont, Dundas and Glengarry United Counties.

Chamberlain was also a director of the Parry Sound Lumber Company, owned by John Classon Miller, the husband of his sister Adelaide Augusta.