| National Association of Testing Authorities | Academic & Science |
| National Aptitude test for Architecture | Academic & Science |
| Natural Areas Training Academy | Academic & Science |
| Northern Air Transport Association | Associations & Organizations |
| National Air Transportation Association | Business |
| National Association of Temple Administrators | Business |
| Nepal Association of Travel Agents | Business |
| Nebraska Art Teachers Association | Business |
| National American Telecommunications Association | Business |
| North American Trainer Association | Community |
| North American Telugu Association | Community |
| Nebraska Association of Trial Attorneys | Community |
| National Association for Temple Administration | Community |
| NW Automotive Trades Association | Community |
| North America Tibetan Associations | Community |
| National Alliance of Trade Associations | Community |
| North Atlantic Tourism Association | Community |
| Nigeria Automobile Technicians Association | Community |
| National Automobile Transporters Association | Community |
| Northwest Automotive Trades Association | Community |
| North American Telephone Association | Computer and Networking |
| North American Telecommunications Association | Computing |
| National Aptitude Test in Architecture | Engineering Entrance Exam in India |
| Nuts About Tatting Association | General |
| Nebraska Aviation Trades Association | General |
| Northwest Automotive Traders Association | General |
| North Area Transport Association | General |
| National Automotive Trades Association | General |
| National Anti Terrorist Association | Governmental |
| Netley Abbey Tartan Army | Governmental |
| National Air Toxics Assessment | Governmental |
| North Area Transportation Alliance | Governmental |
| National Athletic Trainers' | Sports |
| National Athletic Trainers Assossiation | Sports |
| National Athletic Trainers Association | Sports |
