Aer Lingus Group Plc (ISEQ: EIL1, LSE: AERL) (an anglicisation of the Irish Aer Loingeas meaning grossly "air fleet") is the flag carrier of Ireland. It operates a fleet of Airbus aircraft serving Europe and North America. It is Ireland's oldest extant airline, and its second largest after low-cost rival Ryanair. The airline's head office is located on the grounds of Dublin Airport.

Formed in 1936, Aer Lingus is a former member of the Oneworld airline alliance, which it left on 31 March 2007. While it is not part of an alliance, the airline has codeshares with Oneworld, Star Alliance and SkyTeam members, as well as interline agreements with Aer Arann and JetBlue Airways. The company employs 4,000 people and in 2010 had revenues of €1.2 billion. Aer Lingus flew 9.3 million passengers in 2010. It has a mixed business model, operating a low fare service on its European and North African routes and full service, two-class flights on transatlantic routes.

Aer Lingus is 29.4% owned by its rival, Ryanair, and 25.4% owned by the Government of Ireland. The airline was floated on the Dublin and London Stock Exchanges on 2 October 2006, following prior government approval (the government previously owned 85% of the airline). The principal group companies include Aer Lingus Limited, Aer Lingus Beachey Limited, Aer Lingus (Ireland) Limited and Dirnan Insurance Company Limited, all of which are wholly owned.