| Acquisition Tuition Assistance Program | Academic & Science |
| Associate Teacher Accreditation Program | Academic & Science |
| Accelerator Technology and Applied Physics | Academic & Science |
| Assistive Technology Access Partnership | Business |
| Association of Tax Accounting Professionals | Business |
| Agreement on Trade in Agricultural Products | Business |
| Advanced Technologies And Products | Business |
| Academy of Theatre Arts Performance | Community |
| Aircraft Technologists Association of Pakistan | Community |
| Association of Tech Act Projects | Community |
| Australian Tourism Accreditation Program | Community |
| Association of Talent Acquisition Professionals | Community |
| Association of Threat Assessment Professionals | Community |
| American Theatre Archive Project | Community |
| Arm Technology Access Program | Computing |
| Advanced Technologies and Projects | Computing |
| Advanced Technology and Projects | Computing |
| Assistive Technology Act Programs | Computing |
| Approximation Theory and Approximation Practice | General |
| Allied Trades Assistance Program | General |
| Alcohol Training Awareness Program | General |
| Acoustic Tracking Array Platform | General |
| All Things Are Possible | General |
| Asteroid Threat Assessment Project | General |
| Arkansas Taxpayer Access Point | General |
| Anterior Tibialis Artery Perforator | General |
| Anti Tank Anti Personnel | General |
| Auckland Transport Alignment Project | General |
| Azienda Trasporti Automobilistici Provinciali | General |
| Australian Transport Assessment and Planning | General |
| Asociacion de Transporte Automotor de Pasajeros | General |
| Australian Truck and Auto Parts | General |
| Anti-Terrorism Assistance Program | Governmental |
| Anti-Terrorist Action Plan | Governmental |
| Alabama Telecommunications Access Program | Governmental |
| Alabama Transportation Assistance Program | Governmental |
| Army Talent Alignment Process | Governmental |
| Autism Treatment Assistance Program | Medical |
| Alaska Temporary Assistance Program | Regional |
| Alaska Transportation Alternatives Program | Regional |
| Australian Truck Auto Parts | Regional |
