| Abbreviation | Definition |
|---|---|
| ISSMO | International Society for Structural and Multidisciplinary Optimization |
| ISSOFBC | Immigrant Services Society of British Columbia |
| ISSP | International Society for Sports Psychiatry |
| ISSP | International Society of Safety Professionals |
| ISSP | International Society of Sustainability |
| ISSP | International Society of Sustainability Professionals |
| ISSP | Irish Society of Surgical Pathology |
| ISSPD | International Society for the Study of Personality Disorders |
| ISSPORTH | International Society for Sport Traumatology of the Hand |
| ISSPR | International Society for the Study of Personal Relationships |
| ISSRT | Illinois State Society of Radiologic Technologists |
| ISSS | Information Society Standardisation System |
| ISSS | Interdisciplinary Science Students Society |
| ISSS | International Society for the System Sciences |
| ISSSS | International Society for the Scientific Study of Subjectivity |
| ISSSS | International Society for the Social Sciences of Sport |
| ISST | International Society for Sandplay Therapy |
| ISST | International Society of Schema Therapy |
| IST | Information Society Technologies |
| IST | Irish Society of Toxicology |