Sidney Smith may refer to:
Sir William Sidney Smith (1764–1840), British admiral, always known as Sir Sidney Smith
Rev. Sydney Smith (1771–1845), English writer and clergyman
Sidney Smith (lawyer) (1823–1889), lawyer and politician in Upper Canada
Sidney Irving Smith (1843–1926), American zoologist
Sidney Smith (cartoonist) (1877–1935), American cartoonist
Sidney Smith (American football), American college football coach in 1905
Sidney Smith (Assyriologist), (1889–1979) institute director and academic
Sidney Earle Smith (1897–1959), Canadian university president and Secretary of State for External Affairs
Sidney Walter Smith (1893–1981), New Zealand politician
Sidney Oslin Smith Jr. (1923–2012), United States federal judge
Sidney R. J. Smith, (1858–1913) architect - designer of many of the buildings funded by Henry Tate's philanthropy
Sidney Smith (photographer), fl. first half of the 20th century; English photographer
Sidney Smith (snooker player)