IAA

IAA is a three letter initialism that may stand for:

In science and medicine

• Indole-3-acetic acid (plant hormone)
• Insulin autoantibody, used in diagnosing Latent autoimmune diabetes
• Interrupted aortic arch
• Intravenous ascorbic acid therapy for cancer or sepsis
• International Association for Aerobiology
• International Association of Astacology, for the study of Crayfish

In healthcare organisations

• Independent Ambulance Association representing private ambulance services in the United Kingdom

In aviation

• Indianapolis Airport Authority
• Iran Aseman Airlines, call-sign IAA
• Irish Aviation Authority
• Israel Airports Authority

In computing

• Interactive Achievement Awards

In education

• Idyllwild Arts Academy, part of the Idyllwild Arts Foundation
• IMSA Alumni Association
• Intercollegiate Athletic Association (formerly), now the National Collegiate Athletic Association (NCAA)
• Interlochen Arts Academy, part of the Interlochen Center for the Arts
• International Affairs Association of the University of Pennsylvania

In sport

• International Ammunition Association
• International Aquathlon Association

Other associations

• Immigration Appellate Authority (UK)
• Indian Agricultural Association
• Indian Association of Alberta
• Institute for Alternative Agriculture
• Institute for Applied Autonomy
• Institute of Actuaries of Australia
• Instituto de Arqueología Amazónica
• Instituto de Astrofísica de Andalucía
• International Academy of Architecture
• International Academy of Astronautics
• International Actuarial Association
• International Advertising Association
• International Alpaca Association
• Investment Adviser Association
• Irrigation Association of Australia
• Islamic Army of Aden
• Israel Antiquities Authority
• Israel Israeli Astronomical Association

Other uses

• Intelligence Authorization Act (1991 - U.S.)
• Internationale Automobil-Ausstellung, Frankfurt Motor Show