| Acronym | Definition |
|---|
| SIIS➣Statewide Immunization Information System |
| SIIS➣Shanghai Institute for International Studies (international relations research organization; Shanghai, China) |
| SIIS➣State Industrial Insurance System (Nevada) |
| SIIS➣Southwestern Insurance Information Service |
| SIIS➣Subsea Instrumentation Interface Standardisation (electronics equipment protocol) |
| SIIS➣Spacecraft/Instrument Interface Simulator |
| SIIS➣Seikei Institute for International Studies (Seikei University; Japan) |
| SIIS➣Stanford University's Institute for International Studies |