IA, Ia, or ia may refer to:
Sir Ian Murray McKellen (born 25 May 1939) is an English actor. His career spans genres ranging from Shakespearean and modern theatre to popular fantasy and science fiction.
Sir Ian Terence Botham (born 24 November 1955) is a British cricket commentator and a former cricketer who has been chairman of Durham County Cricket Club since 2017. Widely regarded as one of the greatest all-rounders in cricket history, Botham represented England in both Test and One-Day International cricket.
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 Edward Wright, (born 3 November 1963) is an English former professional footballer and television and radio personality.
Ian Richard Kyle Paisley, Baron Bannside (6 April 1926 – 12 September 2014), was a loyalist politician and Protestant religious leader from Northern Ireland.
Ian Kevin Curtis (15 July 1956 – 18 May 1980) was an English singer-songwriter and musician. He was the lead singer and lyricist of the post-punk band Joy Division and recorded two albums with the group: Unknown Pleasures (1979) and Closer (1980).
George Iain Duncan Smith (born 9 April 1954), often referred to by his initials IDS, is a British Conservative Party politician.
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.