Duncan Smith may refer to:
Duncan Smith (Australian politician) (1890–1973), Australian politician Duncan Smith (Irish politician) (born 1983), Irish Labour politician Duncan Smith (footballer) (born 1929), Scottish footballer Duncan J. D. Smith (born 1960), British travel writer, photographer, historian, and explorer Duncan Smith (cricketer), British cricket player
See also Iain Duncan Smith (born 1954), British Conservative politician William Duncan Smith (1825–1862), United States Army officer who fought in the Mexican–American War W. G. G. Duncan Smith (1914–1996), British Royal Air Force Second World War Flying ace George Smith Duncan (1852–1930), tramway and mining engineer best known for his work on cable trams