Ian or Iain Campbell may refer to:
- Ian Campbell (rugby union) (1928–2022), Chilean rugby union footballer, of Scottish descent
- Iain Campbell (footballer) (born 1985), Scottish footballer
- Ian Campbell (triple jumper) (born 1957), Australian long and triple jumper
- Iain Campbell (cricketer) (1928–2015), English cricketer and headmaster
- Ian Campbell (Middlesex cricketer) (1870–1954), English cricketer
- Ian Campbell (Queen's Park footballer) (fl. 1965–1977), Scottish football player (Queen's Park FC)
- Ian Campbell (footballer, born 1953), Scottish football player and manager (Brechin City FC)
- Ian Campbell (American football) (born 1985), Kansas State Wildcats college football player
- Iain Campbell (swimmer) (born 1965), British swimmer
- Ian Campbell (Royal Navy officer) (1898–1980), British admiral
- Ian Ross Campbell (1900–1997), Australian soldier and businessman
- Ian Campbell, 11th Duke of Argyll (1903–1973), Scottish peer
- Ian MacDonald Campbell (1922–1994), British civil engineer
- Ian James Campbell (1931–1963), murdered Los Angeles, California police officer
- Ian Campbell, 12th Duke of Argyll (1937–2001), Scottish Peer and Chief of Clan Campbell
- Iain Donald Campbell (1941–2014), Scottish biophysicist
- Ian Campbell (apothecary) (active circa 1992–2007), former officer of the British Medical Household
- Iain D. Campbell (1963–2017), minister in the Free Church of Scotland
- Ian L. Campbell (born 1945), British historian specialising in Ethiopia