| IISS | ICON Incentive Scoring System 
| Others |
| IISS | ICON Incentives Scoring System
| Others |
| IISS | Imperial Interstellar Scout Service
| Others |
| IISS | Indian Institute of Soil Science
| Others |
| IISS | Institute for Integrated Sensor Systems
| Others |
| IISS | Institute of International and Strategic Studies
| Others |
| IISS | Integral Input to State Stability
| Others |
| IISS | Integrated Information Support System
| Others |
| IISS | Intelligence Information Sharing Standards
| Others |
| IISS | Intensive Individual Support Services
| Others |
| IISS | Interactive Image Spread Sheat
| Others |
| IISS | Intercultural and Inclusion Student Services
| Others |
| IISS | Intercultural and International Student Services
| Others |
| IISS | Interdisciplinary Islamic Studies Seminar
| Others |
| IISS | International and Immigrant Student Services
| Others |
| IISS | International Image Sensor Society
| Others |
| IISS | International Infrastructure Support System
| Others |
| IISS | International Institute for Strategic Studies
| Military, Defence, Institute, Research Center |
| IISS | Israel Institute for Strategic Studies
| Others |