IAA is a TLA that may stand for:
- I am alive (disaster support system)
- Identification, authentication and authorization
- Immigration Appellate Authority (UK)
- IMSA Alumni Association (iaa.org)
- Indianapolis Airport Authority
- Indian Association of Alberta
- Indole-3-acetic acid (plant hormone)
- Inflammatory aortic aneurysm
- Information Age Associates (iaa.com)
- Information Appliance Associates
- Infrarenal aortic aneurysm
- Institute for Academic Access
- Institute for Alternative Agriculture
- Institute for Applied Autonomy
- Instituto de Arqueología Amazónica
- Instituto de Astrofísica de Andalucía (iaa.es)
- Insulin autoantibody
- Insurance Application Architecture
- Intel Application Accelerator
- Interactive Amusement Association
- Interlochen Arts Academy
- International Academy of Astronautics
- International Actuarial Association
- Inter-National Adoption Alliance
- International Advertising Association
- International Airport of Atyrau
- International Alpaca Association
- International Ammunition Association
- International Art Academy (iaa.it)
- International Association for Aerobiology
- International Association of Astacology
- Internationale Automobil-Ausstellung (iaa.de)
- Internet Applications Architecture
- Interrupted aortic arch
- Irish Aviation Authority (iaa.ie)
- Irrigation Association of Australia
- Islamic Action Association
- Islamic Army of Aden
- Islamic Association of Australia
- Israel Advertising Association
- Israel Antiquities Authority
- Israel Airports Authority
- IAA Aerospace Group