FAI, used as an acronym, may refer to:
- FAI armoured car, a Soviet military vehicle of the early 1930s
- FAI Films, a defunct Australian film production company
- Fairbanks International Airport (IATA code 'FAI'), a public airport near the city of Fairbanks, Alaska, United States
- Fatal accident inquiry, a Scottish legal aspect, used when a fatal accident has occurred.
- Federación Anarquista Ibérica, "Iberian Anarchist Federation"
- Fédération Aéronautique Internationale, "FAI - The World Air Sports Federation"
- Federazione Anarchica Informale (Informal Anarchist Federation), Italian organization of direct action anarchist factions
- Federazione Anarchica Italiana (Italian Anarchist Federation), founded in 1945 in Carrara
- Femoral Acetabular Impingement, a condition affecting the hip joint.
- Financial Access Initiative, a research consortium
- First article inspection
- Fixed asset investment
- Fondo per l'Ambiente Italiano, "Italian Environment Fund"
- Football Association of Ireland, for football (soccer) in the Republic of Ireland.
- Food Allergy Initiative, a US based non-profit organization which funds research and seeks a cure for food allergies
- Food Animal Initiative, Oxford based, global, sustainable farming research and development organisation
- Fournisseur d'accès à Internet, French term for Internet service provider, an organization that sells access to the Internet
- Free Androgen Index
- Frente Amplio de Izquierda, Broad Left Front, a political coalition in Peru
- Friendly artificial intelligence
- Fresh air intake, in HVAC systems, an opening through which outside air is drawn into a building.
- Fully Automatic Installation, for non-interactive installation of the Debian GNU/Linux operating system
Fai may refer to:
- Sonny Fai, New Zealand rugby league player
- Fay D. Flourite (misnamed 'Fai' in some versions), a character from Tsubasa: RESERVoir CHRoNiCLE