NAA is an acronym for;
- National Aeronautic Association, American Air Transport Association
- National Archives of Australia, the National Archives of Australia
- Nomina Anatomica Avium, the anatomical nomenclature for birds, see Nomenclature ( anatomy)
- Nuremberg Astronomical Association
- Neutron Activation Analysis
- Newspaper Association of America, the Association of Newspaper Publishers in the United States.
- N-acetyl- aspartate, a metabolite of the brain metabolism
- Node -Arc Area, topological model
- 1- naphthalene acetic acid, a substituted acetic acid
- North American Airlines, an American charter airline
- North American Arms, an American weapons manufacturer
- North American Aviation, a former American aircraft manufacturer.