Sidney Earle Smith (March 9, 1897-March 17, 1959) was a noted academic and Canada's Secretary of State for External Affairs under John Diefenbaker.

Born in a poor area of Cape Breton, he grew up speaking both English and Gaelic. He was an excellent student and became a lawyer and then professor of law. He lectured first at Osgoode Hall and then at Dalhousie University and by 1929 was Dean of that university's law school. In 1934 he left the Maritimes to become president of the University of Manitoba. In 1945 he was appointed president of the University of Toronto. He remained in that role for twelve years, overseeing the university's greatest period of expansion.

Long a strong Conservative, but very much in the Red Tory tradition, Smith became a prominent member of the Progressive Conservative Party. In 1956 he was considered a possibility for the party's leadership, but decided not to run, disappointing those who wished to prevent the populist John Diefenbaker from becoming leader.

After Diefenbaker won a surprise minority government in 1957 Smith was appointed to head the External Affairs department. Despite Smith's brilliance and popularity in academia, his success in this new role was limited and the government's foreign policy ran into a series of problems under Smith. After only holding the position for two years Smith died suddenly in 1959.

Sidney Smith Hall, the main Arts & Science building at the University of Toronto, is named after him.[[Category:Presidents of the University of Toronto}Smith]]