IA, Ia, or ia may refer to:
Sir Ian Murray McKellen (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.
Sir Ian Terence Botham, OBE (born 24 November 1955) is an English former cricketer and current cricket commentator.
Ian Richard Kyle Paisley, Baron Bannside (6 April 1926 – 12 September 2014), was a loyalist politician and Protestant religious leader from Northern Ireland.
Ian Edward Wright, (born 3 November 1963) is an English former professional footballer and television and radio personality.
Ian James Thorpe, (born 13 October 1982) is a retired Australian swimmer who specialised in freestyle, but also competed in backstroke and the individual medley.