Ian McDonald may refer to:

  • Ian McDonald (civil servant) (1936−2019), Ministry of Defence spokesman during the Falklands War
  • Ian McDonald (musician) (1946−2022), member of King Crimson, 1969−1970, and Foreigner, 1977−1979
  • Iain Matthews (born 1946), previously known as Ian McDonald, member of Fairport Convention
  • Ian Hamilton McDonald (1923−2019), Australian cricketer
  • Ian McDonald (footballer, born 1951) (born 1951), Scottish football midfielder with Darlington
  • Ian McDonald (footballer, born 1953), English football midfielder with York City and Aldershot, among others
  • Ian McDonald (footballer, born 1958) (born 1958), Scottish football midfielder with Partick Thistle and Greenock Morton, among others
  • Ian McDonald (Guyanese writer) (born 1933), Caribbean-born writer
  • Ian McDonald (British author) (born 1960), British science fiction novelist
  • Ian Donald Roy McDonald (1898−1920), World War I flying ace
  • W. Ian McDonald (1933−2006), New Zealand neurologist, academic, and specialist in multiple sclerosis

Ian MacDonald may refer to:

  • Ian MacDonald (1948−2003), pen-name for British music critic Ian MacCormick
  • Ian MacDonald (footballer) (born 1953), Scottish football defender with St. Johnstone and Carlisle, among others
  • Ian MacDonald (oceanographer), American Biological Oceanographer, Florida State University
  • Ian MacDonald (actor) (1914−1978), American actor and producer
  • Ian MacDonald (Canadian politician), former public school teacher and former Mayor of Charlottetown, Prince Edward Island, Canada
  • Ian Macdonald (Australian politician, born 1945), Australian federal politician
  • Ian Macdonald (Scottish politician) (born 1934), Scottish nationalist activist
  • Ian Macdonald (barrister) (1939−2019), Scottish barrister
  • Ian Macdonald (New South Wales politician) (born 1949), former Australian state politician
  • Ian G. Macdonald (1928−2023), British mathematician
  • L. Ian MacDonald (born 1947), Canadian writer, broadcaster, and diplomat
  • H. Ian Macdonald (born 1929), Canadian economist, civil servant, and President of York University, 1974−1984
  • Ian MacDonald (architect) (born 1953), Canadian architect
  • Ian Verner Macdonald (1925–2022), Canadian writer and diplomat
  • Ian MacDonald (physician) (1873−1932), Scottish physician
  • Ian MacDonald (rugby union) (born 1968), South African rugby union player
  • Ian Macdonald, Canadian musician, keyboard player for the 1990s band Punchbuggy
  • Ian Macdonald, character in the 1927 film Annie Laurie

Iain MacDonald or McDonald may refer to:

  • Iain MacDonald (businessman), Irish entrepreneur
  • Iain B. MacDonald, British television director
  • Iain Fraoch MacDonald (died 1368), founder of Clan MacDonald of Glencoe
  • Iain Sprangach MacDonald (died 1340), founder of Clan MacDonald of Ardnamurchan
  • Iain McDonald (born 1952), Scottish football winger with Rangers and Dundee United
  • Iain MacDonald, Scottish bagpiper, one of the MacDonald Brothers