| Academic Technologies Advisory Committee | Academic & Science |
| Academy of Texas Aquatic Champions | Academic & Science |
| All Terrain All Climate | Academic & Science |
| Aftermarket Technology Corporation | Business |
| Air Transport Association of Canada | Business |
| Avionics Test And Analysis Corporation | Business |
| Academic Technology Advisory Council | Business |
| Academic Technology Advisory Committee | Business |
| Accountability Technical Advisory Committee | Business |
| Agricultural Technical Advisory Committees | Business |
| Airborne Tactical Advantage Company | Business |
| Arizona Transfer Articulation Committee | Community |
| Accelerated Technical Assistance for Conservation | Community |
| area Tallahassee aquatic club | Community |
| Abusable Technologies Awareness Center | Computing |
| Assistive Technology Advocacy Center | Computing |
| Alternative Technology Advisory Committee | Computing |
| Assistive Technology Advisory Committee | Computing |
| Advanced Technology and Application Center | Computing |
| Auto Tension Adjustment Concept | General |
| Automatic Targeting Attack Communicator | General |
| All Topics Are Considered | General |
| Aids Treatment Activists Coalition | General |
| Advanced Traceability And Control | General |
| Active Thermo Atmosphere Combustion | General |
| Auto Theft Advisory Committee | General |
| Advanced Automotive Technology Certificate | General |
| Adic Technical Assistance Center | General |
| Advanced Thermal Alloy Construction | General |
| Aphis Technical Assistance Center | General |
| Advanced Traffic Analysis Center | General |
| Asbestos Testing and Consultancy | General |
| Authenticity Tenacity Audacity and Capacity | General |
| Active Threat Acquisition Calibratoradvanced | General |
| All Terrain All Condition | General |
| Automated Ticket Agent Checkout | General |
| Avenging the Ancestors Coalition | General |
| Automated Ticketing and Accounts Control | General |
| Auto Tension Adjust Concept | General |
| Alternating Two Aluminum Composite | General |
| Addiction Treatment Advocacy Coalition | General |
| Anti Terrorism Advisory Council | Governmental |
| Army Travel Assistance Center | Governmental |
| Aviation Electronics Technician (aircraft) | Governmental |
| American Teens Against Crime | Governmental |
| Antibody Therapy Against Coronavirus | Medical |
| All Terrain Armored Combatant | Military and Defence |
| Anti-terrorism Alert Center | Military and Defence |
| Air-to-air Combat | Military and Defence |
| Alaska Telehealth Advisory Council | Regional |
| African Technical Advisory Committee | Regional |
| Alaska Telehealth Advisory Commission | Regional |
| Administrative Tribunal Advocates of Canada | Regional |
| Assistive Technology and Augmentative Communication | Technology |
| Advanced Technology and Academic Centre | Technology |
| Aerospace Technology Advisory Committee | Technology |
| Atacacademic Technology Advisory Committee | Technology |
| Assistive Technology and Augmentative Com | Technology |
