AFI, the three letter acronym, may refer to:
- AFI (band), an American alternative rock band
- AFI (album), a retrospective album by AFI released in 2004
- Air Force Instruction, documented instructions for members of the United States Air Force
- American Film Institute, an independent non-profit film organization
- American Football Israel, a nonprofit sports organization
- Amniotic fluid index, a measure of the amount of amniotic fluid of a fetus
- Aquarium Fish International, a monthly magazine
- Armed Forces Insurance, insurance company for American military professionals
- Australian Film Institute, an organisation that promotes Australian film and television
- Agencia Federal de Investigación or Federal Investigations Agency, a Mexican agency
- Nikon AF-I, designation for "AutoFocus Internal" Nikon AF lenses
- Application Family Identifier, code of an RFID tag or the Routing Information Protocol