| Abbreviation | Definition |
|---|---|
| ISHS | Inter School Horse Show |
| ISI | International School of Indiana |
| ISIB | International School Ikast Brande |
| ISIB | International School Ikast-Brande |
| ISJ | In School Jobs |
| ISJ | Independent School of Jakarta |
| ISK | Indian School Kuwait |
| ISK | Intermediate School Killorglin |
| ISK | International School of Kenya |
| ISK | International School of Koje |
| ISK | International School of Krakow |
| ISL | Independent School League |
| ISL | International School Of Louisiana |
| ISLG | Inter School Liaison Group |
| ISLP | Instructional School Leadership Program |
| ISLP | International School Leadership Program |
| ISLS | Interdisciplinary School of Life Sciences |
| ISLT | In School Law and Trade |
| ISM | International School of Milan |
| ISM | International School of Minnesota |