| Acronym | Definition |
|---|
| IRTA | Institut de Recerca i Tecnologia Agroalimentàries (Institute of Agricultural-Alimentary Research and Technology) |
| IRTA | International Reciprocal Trade Association |
| IRTA | Intramural Research Training Award |
| IRTA | Institute for Research and Technical Assistance |
| IRTA | Illinois Retired Teachers Association |
| IRTA | Irish Rider Training Association |
| IRTA | Indiana Retired Teachers Association |
| IRTA | International Racing Teams Association |
| IRTA | Immigration Review Tribunal of Australia |
| IRTA | International Retired Tugboat Association |
| IRTA | I Read That As |
| IRTA | In-Reactor Thimble Assembly |
| IRTA | Industrial-Recreational Building Authority (Rhode Island) |