| Abbreviation | Definition |
|---|---|
| ISSA | International Sailing School Association |
| ISSA | International Slalom Skateboarding Association |
| ISSA | International Social Security Association |
| ISSA | International Sociology of Sport Association |
| ISTA | Illinois Soil Testing Association |
| ISTA | International Sound Therapy Association |
| ISTA | International Strength Training Association |
| ISVA | Independent Surveyors and Valuers Association |
| ISWA | Idaho Solid Waste Association |
| ISWA | International Science Writers Association |
| ISWA | International Solid Waste Association |
| ITA | Indoor Tanning Association |
| ITA | Industrial Truck Association |
| ITA | International Titanium Association |
| ITA | International Trombone Association |
| ITAB | Industry Training Association Building |
| ITAC | Indigenous Tourism Association of Canada |
| ITAN | Information Technology Association Nigeria |
| ITASA | Intercollegiate Taiwanese American Student Association |
| ITBA | Independent Theater Bloggers Association |