| ATRA | Advanced Transit Association 
| Others |
| ATRA | Afghan Telecommunications Regulatory Authority
| Others |
| ATRA | Alabama Towing and Recovery Association
| Others |
| ATRA | Alberta Tobacco Reduction Alliance
| Others |
| ATRA | All Trans Retinoic Acid
| Others |
| ATRA | Alternative Transportation Recreational Association
| Others |
| ATRA | American Tax Relief Act
| Others |
| ATRA | American Taxpayer Relief Act
| Others |
| ATRA | American Thailand Ridgeback Association
| Others |
| ATRA | American Therapeutic Recreation Association
| Others |
| ATRA | American Tort Reform Association
| Others |
| ATRA | American Trail Running Association
| Others |
| ATRA | Arizona Tax Research Association
| Others |
| ATRA | Arkansas Teenage Rodeo Association
| Others |
| ATRA | Attention Thieving Rabid Anteater
| Others |
| ATRA | Australian Tire Recyclers Association
| Others |
| ATRA | Auto and Truck Recyclers Association
| Others |
| ATRA | Automatic Transmission Rebuilders Association
| Others |
| ATRA | The Automatic Transmission Rebuilders Association
| Others |