| Acronym | Definition |
|---|
| NSA | National Security Agency (US government) |
| NSA | Naval Support Activity |
| NSA | Not Seasonally Adjusted |
| NSA | Notary Signing Agent |
| NSA | Network Security Appliance (Sonicwall) |
| NSA | National Speakers Association |
| NSA | National Security Advisor |
| NSA | National Security Archive |
| NSA | No Strings Attached |
| NSA | National Security Act |
| NSA | National Sheriffs' Association (Alexandria, VA, USA) |
| NSA | National Security Affairs |
| NSA | National Stroke Association |
| NSA | Non-State Actor (international relations) |
| NSA | National Stuttering Association |
| NSA | National Sheep Association (Malvern, Worcestershire, UK) |
| NSA | National Society of Accountants |
| NSA | North Slope of Alaska |
| NSA | National Scrabble Association |
| NSA | Norwegian Shipowners’ Association |
| NSA | Network Spinal Analysis |
| NSA | National Spiritual Assembly (Institution of the Baha'i Faith) |
| NSA | New Saint Andrews College (Moscow, Idaho) |
| NSA | National Sound Archive |
| NSA | No Sugar Added |
| NSA | National Student Association |
| NSA | Negotiated Service Agreement (US postal service) |
| NSA | National Stereoscopic Association |
| NSA | NATO Standardization Agency |
| NSA | National Steeplechase Association |
| NSA | Nebraska Statewide Arboretum |
| NSA | National Security Area |
| NSA | National Safety Associates |
| NSA | Negative Security Assurances |
| NSA | National Stone Association (Washington, DC) |
| NSA | National Sunflower Association |
| NSA | National Smokers Alliance |
| NSA | Nuclear Science Abstracts |
| NSA | Normalized Site Attenuation |
| NSA | Non-Standard Analysis |
| NSA | National Storytelling Association |
| NSA | National Security Agents (gaming clan) |
| NSA | North Star Academy |
| NSA | Northern Study Area |
| NSA | National School of Administration (China) |
| NSA | Noise Sensitive Area |
| NSA | National Slag Association (Alexandria, VA) |
| NSA | National Shipping Authority |
| NSA | Non-surgical Sperm Aspiration |
| NSA | National Supers Agency (fictional from the movie The Incredibles) |
| NSA | Nunavut Settlement Area |
| NSA | National Security Anarchists (hacker group) |
| NSA | National Sprint Association (UK) |
| NSA | Nikkei Stock Average |
| NSA | Natuurwetenschappelijke Studievereniging Amsterdam (University of Amsterdam Physics Department student organization) |
| NSA | Navy Support Activity |
| NSA | New Statistical Account (Reports on the conditions of Scotland, with reports on each parish, in the 1830s) |
| NSA | Nebraska Soybean Association |
| NSA | Naperville Soccer Association |
| NSA | National Skateboard Association |
| NSA | No Smoking Area |
| NSA | National Safety Association |
| NSA | National Softball Association, Inc. |
| NSA | Norcross Soccer Association (Georgia) |
| NSA | Naval Supervising Activity |
| NSA | National Scout Association |
| NSA | National Singles Association (Atlanta, Georgia) |
| NSA | Navy Stock Account |
| NSA | Night Stalker Association |
| NSA | National Success Association |
| NSA | National Shuffleboard Association |
| NSA | Northern Slope of Alaska |
| NSA | National Software Alliance |
| NSA | National Service Alliance, LLC |
| NSA | National Sentinel Audit |
| NSA | Nantucket Shellfish Association (Nantucket, MA) |
| NSA | Non Standard Area (of a database) |
| NSA | National Standard Application |
| NSA | Narrow-Slot Approximation |
| NSA | Node Switching Assembly |
| NSA | Nuclear Support Agency |
| NSA | Network Search Algorithm |
| NSA | Naval Systems Analysis |
| NSA | Narrow Slot Aperture |
| NSA | Nichiren Shosu of America |
| NSA | Neutron Source Assembly |
| NSA | Network South Australia (Adelaide, Australia) |
| NSA | Net Server Assistant |
| NSA | Norwegian Security Act |
| NSA | Nabelschnurarterie (German: Umbilical Cord Artery) |
| NSA | Nikkei Student Association |
| NSA | Nikkei Siam Aluminium Limited (Pathumtani, Thailand) |