| Abbreviation | Definition |
|---|---|
| ISMS | Indian Springs Middle School |
| ISMS | Isaac L Sowers Middle School |
| ISMS | Isaac Sowers Middle School |
| ISMT | International School of Milling Technology |
| ISMT | International School of Modern Technology |
| ISMW | Indian School of Microfinance for Women |
| ISNA | International School Nurses of Asia |
| ISNP | Imagine School at North Port |
| ISNP | International School of Nanophotonics and Photovoltaics |
| ISNS | International School of Nanshan Shenzhen |
| ISOB | International School of Bergen |
| ISOB | International school of Brno |
| ISOB | International School of Bydgoszcz |
| ISOCS | International School of Central Switzerland |
| ISOF | Institute for Schools of the Future |
| ISOG | Intel School of Genius |
| ISOM | Indiana School of Ministry |
| ISOM | International School of Ministry |
| ISOM | Iowa School of Ministry |
| ISOP | International School of Paphos |