NAA can refer to:
- 1-naphthaleneacetic acid - synthetic auxin (organic compound and plant hormone)
- N-Acetylaspartate, a neurochemical often imaged in magnetic resonance spectroscopy
- NAA, a radio station in Cutler, Maine, operated by the United States Navy
- Naa Govindasamy
- Narita International Airport Corporation
- Narrabri Airport in IATA code NAA
- National Academy of Arbitrators
- National Academy of Arts of Bulgaria
- National Aeronautic Association
- National Airworthiness Authority
- National Anthropological Archives
- National Archives of Australia
- National Assessment Agency
- National Association of Actors, a Mexican television and motion picture performers union.
- National Auctioneers Association
- National Aviation Academy
- National Aviation Authority
- Neutron activation analysis
- Newspaper Association of America, a trade association
- Nigerian Accounting Association
- No abstract available bias
- North American Airlines
- North American Arms, an arms company
- North American Aviation