| Acronym | Meaning |
| NAIMA | North American Insulation Manufacturers Association |
| NAIP | Non-Apatite Inorganic Phosphorus |
| NAIP | Neuronal Apoptosis Inhibitory Protein |
| NAL | No Action Level |
| NAMA | National Air Monitoring Audits |
| NAMAS | National Measurement Accreditation Service (UK) |
| NAME | Nuclear Accident Modeling Exercise [a Model] |
| NAMF | Non-asbestos Mineral Fibers |
| NAMICS | North American Chapter Of The International Chemometrics Society |
| NAMS | National Air Monitoring Station |
| NAMS | Neutron Activation Mass Spectrometry |
| NAMT | National Advanced Manufacturing Testbed |
| NAO | Natural Atomic Orbital |
| NAPAP | National Acid Precipitation Assessment Program |
| NAPBN | National Air Pollution Background Network |
| NAPCA | National Air Pollution Control Administration |
| NAPIAP | National Agricultural Pesticide Impact Assessment Program |
| NAPIM | National Association Of Printing Ink Manufacturers (US) |
| NAPIS | National Agricultural Pest Information System |
| NAPL | Nonaqueous Phase Liquid |
| NAPPA | Nucleic Acid Programmable Protein Array |
| NAPRI | North American Pollutant Release Inventory |
| NARA | United States National Archives And Records Administration |
| NARE | North Atlantic Regional Experiment |
| NAREL | National Air And Radiation Environmental Laboratory |
| NARL | National Air And Radiation Laboratory |
| NARS | National Asbestos Registry System |
| NARSTO | North American Research Strategy For Tropospheric Ozone |
| NARSTO-NE-OP | North American Research Strategy For Tropospheric Ozone-Northeast Oxidant And Particle Study |
| NAS | National Academy Of Science |
| NAS | Naval Air Station |
| NASA | National Aeronautics And Space Administration |
| NASBA | Nucleic Acid Sequence-based Amplification |
| NASC | North American Shale Composite |
| NASD | National Ag Safety Database |
| NASDA | National Space Development Agency Of Japan |
| NASICON | Na Super-ionic Conductor |
| NASN | National Air Sampling Network |
| NASO | Nasmyth Adaptive Optics System |
| NASP | National Aerospace Plane |
| NASQAN | National Stream Quality Accounting Network |
| NASQUAN | National Stream Water Quality Accounting Network |
| NAT | Nitric Acid Trihydrate (polar Stratosphere Cloud Aerosol) |
| NATA | National Air Toxics Assessment |
| NATAS | North American Thermal Analysis Society |
| NATICH | National Air Toxics Information Clearinghouse |
| NATO | North Atlantic Treaty Organization |
| NAVORDSTA | Naval Ordnance Station (US) |
| NAWDEX | National Water Data Exchange |
| NAWQA | National Water Quality Assessment (US Geological Survey) |