| Acronym | Definition |
|---|
| IIS | Internet Information Services (Microsoft) |
| IIS | Institute of Industrial Science (Japan) |
| IIS | Institute of International Studies |
| IIS | Institut für Integrierte Schaltungen (German: institute for integrated circuits) |
| IIS | Immunization Information Systems |
| IIS | Institute of Ismaili Studies (London, UK) |
| IIS | Integrated Information System |
| IIS | Indian Institute of Science |
| IIS | Iraqi Intelligence Service |
| IIS | Instituto de Investigaciones Sociales (Costa Rica) |
| IIS | International Insurance Society (New York, NY) |
| IIS | Fraunhofer Institut Integrierte Schaltungen |
| IIS | Information Institute of Syracuse |
| IIS | Internet Information System |
| IIS | Institute of Information Scientists |
| IIS | Inter-IC Sound (aka I2S) |
| IIS | Interactive Internet Sports |
| IIS | Ingeniero Industrial Y de Sistemas (Mexico) |
| IIS | Intelligence Information System |
| IIS | International Investigation Services |
| IIS | Information and Intelligence Systems |
| IIS | Infrastructure and Information Systems (division) |
| IIS | Industry Information Security |
| IIS | Image Integration Systems, Inc. |
| IIS | International Iguana Society |
| IIS | Inflationary Impact Statement |
| IIS | Incoming Inspection Standard |
| IIS | Interagency and International Services (Army Corps of Engineers, Directorate of Military Programs) |
| IIS | Intelligent Inference Systems Corporation |
| IIS | IBM Information Services |
| IIS | Intelligent Internet Strategies |
| IIS | Interface Implementation Specification |
| IIS | Israel Information Service |
| IIS | Irreducible Inconsistent Subsystem (linear programming) |
| IIS | Investor Information Service |
| IIS | Industrial Integration Services |
| IIS | Information Indicate String |
| IIS | Institute of Informatic Systems (Novosibirsk, Russia) |
| IIS | Imperial Investor Service |
| IIS | Intelligence Systems Secretariat |
| IIS | Integrated Information Store |
| IIS | Information Integrity Services |
| IIS | ISPO Information System |
| IIS | Imaging Index System |
| IIS | Interfaces to Information Sources |
| IIS | Interim Instrumentation System |
| IIS | Institutional Improvement Specialist (education) |
| IIS | Insurance Information Strategy |
| IIS | Israel Immunological Society |
| IIS | Inter Ikea Systems (Netherlands) |
| IIS | Institute for Social Innovation (Escuela Superior de Administración y Dirección de Empresas) |
| IIS | Irish Institute of Sport (est. 2006; Ireland) |