Smyth is the surname borne by the following people:
- families
- Smyth Baronets, British nobles.
- Bowyer-Smyth Baronets, British nobles.
- individuals
- Alan Smyth, an English music producer.
- Alexander Smyth(1765 – 1830), American general and politician.
- Anthony Smyth, one of the Florida Four, arrested for arms smuggling.
- Bill Smyth, an Australian cricketer.
- Brendan Smyth (priest), an Irish priest.
- Brendan Smyth (politician), an Australian politician.
- Brian Smyth, an Irish artist.
- Bryan Smyth, an Irish actor.
- Cameron Smyth, an American politician.
- Carl Smyth, an English musician also known as "Chas Smash".
- Charles Piazzi Smyth, Astronomer Royal for Scotland.
- Clement Smyth, an Irish Roman Catholic bishop.
- Clifford Smyth, a politician in Northern Ireland.
- Dave Smyth, a British record producer.
- Des Smyth, an Irish golfer.
- Edward Selby Smyth, a British general.
- Eric Smyth, a politician in Northern Ireland, former Lord Mayor of Belfast.
- Ethel Smyth, an English composer and suffragist.
- Frederick Smyth (New Jersey) (1732-1815), Chief Justice of colonial New Jersey.
- Frederick Smyth (New Hampshire) (1819-1899), Governor of New Hampshire.
- Frederick Smyth (New York) (fl 1900s), a justice of the New York Supreme Court.
- George Henry Smyth, an artist from Northern Ireland.
- George Stracey Smyth, British lieutenant-governor of New Brunswick.
- George W. Smyth, a Texan-American politician.
- Gerry Smyth, an Irish academic.
- Gilli Smyth, a British musician.
- Henry DeWolf Smyth, an American physicist.
- Herbert Weir Smyth, an American classicist.
- Hugh Smyth, a politician in Northern Ireland, former Lord Mayor of Belfast.
- James Carmichael Smyth, a British colonial administrator.
- Jimmy Smyth, an Irish guitarist.
- Jimmy Smyth (hurler), an Irish hurler.
- John Prendergast Smyth, 1st Viscount Gort, a British-Irish politician.
- John Smyth (1570-1612), a founder of the Baptist church.
- John Smyth (1748-1811), British Privy Counsellor in 1802.
- John George Smyth (1893-1983), British MP, Privy Counsellor in 1962, recipient of the Victoria Cross during the First World War.
- Malcolm Smyth, an Irish academic.
- Mark Smyth, an English football (soccer) player.
- Martin Smyth, a politician in Northern Ireland.
- Nevill Maskelyne Smyth, a British general and recipient of the Victoria Cross.
- Patty Smyth, an American singer.
- Phil Smyth, an Australian basketball player.
- Richard Smyth, an English theologian and academician.
- Robert Brough Smyth, an Australian geologist.
- Ryan Smyth, a Canadian ice hockey player.
- Sarah Smyth, a Canadian actress.
- Seán Smyth, an Irish violinist.
- Stephen Smyth, an Irish cricketer.
- Steve Smyth, an American musician in the band Nevermore.
- Thomas Smyth, a British-Irish politician.
- Thomas Alfred Smyth, an American general, the last Union general killed in the Civil War.
- Tommy Smyth, an Irish-American sports commentator.
- Warington Wilkinson Smyth, a British geologist.
- William Smyth, an English bishop.
- William Smyth (professor), an American university professor.
- William Henry Smyth, a British astronomer and travel writer.
