Smithson is a common English surname that may refer to:
Alison and Peter Smithson, British architects
Bryan Smithson, American basketball player
Forrest Smithson, American athlete
Gerald Smithson, English cricketer
Harriet Smithson, Henrietta Constance Smithson, actor and wife of Hector Berlioz
Henry Smithson, the musician Riton
Hugh Smithson, (1714–86) later Hugh Percy, 1st Duke of Northumberland
James Smithson, British scientist, eponym of the Smithsonian Institution
Jerred Smithson, NHL player
Jim L. Smithson, former Arkansas state representative
John Smithson, Discovery Channel producer
Mike Smithson (disambiguation), various people
Robert Smithson, American artist
Rodney Smithson, former footballer who played for Oxford United
Charles Smithson, a major character in The French Lieutenant's Woman
