| Acronym | Definition |
|---|
| IISI➣International Iron and Steel Institute |
| IISI➣Institute for Socio-Informatics (Germany) |
| IISI➣Intelligent Information Systems Institute (Cornell University; est. 2000) |
| IISI➣International Integrated Systems, Inc. (est. 1990; Taiwan) |
| IISI➣Intermediary Insurance Services, Inc. (various locations) |
| IISI➣Independent Insurance Solutions Inc. (Fort Myers, FL) |