| ISIM | IBM Security Identity Manager 
| Others |
| ISIM | Improving Simulation Instructional Methods
| Others |
| ISIM | Indian School of Image Management
| Others |
| ISIM | Instant Structured Illumination Microscopy
| Others |
| ISIM | Institute for the Study of International Migration
| Others |
| ISIM | Integrated Science Instrument Module
| Others |
| ISIM | International School of Information Management
| Others |
| ISIM | International Society for Improvised Music
| Others |
| ISIM | International Society for Invertebrate Morphology
| Others |
| ISIM | International Society of Internal Medicine
| Others |