IA, Ia, or ia may refer to:
Sir Ian Murray McKellen, CH, CBE (born 25 May 1939) is an English actor. He is the recipient of six Laurence Olivier Awards, a Tony Award, a Golden Globe Award, a Screen Actors Guild Award, a BIF Award, two Saturn Awards, four Drama Desk Awards, and two Critics' Choice Awards.
Ian Lancaster Fleming (28 May 1908 – 12 August 1964) was an English author, journalist and naval intelligence officer who is best known for his James Bond series of spy novels.
Ian Richard Kyle Paisley, Baron Bannside, PC (6 April 1926 – 12 September 2014) was a loyalist politician and Protestant religious leader from Northern Ireland.
George Iain Duncan Smith (born 9 April 1954), often referred to by his initials IDS, is a British Conservative Party politician.
Ian Edward Wright, MBE (born 3 November 1963) is an English former professional footballer turned television and radio personality.
Ian James Thorpe, OAM (born 13 October 1982) is an Australian swimmer who specialises in freestyle, but also competes in backstroke and the individual medley.
Iain Banks (16 February 1954 – 9 June 2013) was a Scottish author. He wrote mainstream fiction under the name Iain Banks and science fiction as Iain M.
Ian Douglas Smith, GCLM, ID (8 April 1919 – 20 November 2007) was a politician, farmer, and fighter pilot who served as Prime Minister of Rhodesia (or Southern Rhodesia) from 1964 to 1979. The country's first premier not born abroad, he led the predominantly white government that unilaterally declared independence from the United Kingdom in 1965, following prolonged dispute over the terms.