| NAIC | National Astronomy and Ionosphere Center (USA) |
| NARFA | National Allied Radio Frequency Agency |
| NAS | National Academy of Sciences (USA) |
| NASA | National Aeronautics and Space Administration (USA) |
| NASDA | National Space Development Agency of Japan |
| NATO | North Atlantic Treaty Organization |
| NAVSTAR | see GPS |
| NAVTEX | Narrow-band direct-printing telegraphy system for transmission of navigational and meteorological warnings and urgent information to ships |
| NESS | National Environment Satellite Service (of NOAA) |
| NEST | Nuclear Emergency Search Team (USA) |
| NFRA | Netherlands Foundation for Research in Astronomy (NL) |
| NGO | Non Governmental Organization |
| NGSO | Non-Geostationary Satellite Orbit |
| NIST | National Institute of Standards and Technology (USA) |
| NIVR | Nederlands Instituut voor Vliegtuigontwikkeling en Ruimtevaart (NL) |
| NJFA | NATO Joint Civil/Military Frequency Agreement |
| NMR | Network Meter Reading |
| NNSS | Navy Navigational Satellite System (USA) |
| NOAA | National Oceanographic and Atmospheric Administration (USA) |
| NRAL | see JBO |
| NRAO | National Radio Astronomy Observatory (USA) |
| NRC | National Research Council (USA) |
| NSF | National Science Foundation (USA) |
| NTIA | National Telecommunications and Information Administration (USA) |
| NV/NG | Non-voice/Non-geostationary |
| NWS | National Weather Service (USA) |