| Acronym | Definition |
|---|
| IFF | Identification, Friend or Foe |
| IFF | I Feel Fine (Beatles song) |
| IFF | International Film Festival |
| IFF | If and Only If |
| IFF | Interchange File Format |
| IFF | International Flavors and Fragrances |
| IFF | Introduction to Fighter Fundamentals (US Air Force flight training) |
| IFF | Image File Format |
| IFF | Independent Film Festival |
| IFF | Institut Fuer Festkoerperforschung (German: Institute of Solid State Research) |
| IFF | Initial Face-to-Face |
| IFF | International Finance Facility |
| IFF | International Floorball Federation (Helsinki, Finland) |
| IFF | Ischia Film Festival (Italy) |
| IFF | International Food Festival |
| IFF | Fraunhofer-Institut für Fabrikbetrieb und -Automatisierung (German: Fraunhofer Institute for Factory Operation and Automation) |
| IFF | International Feldenkrais Federation (education; est. 1992) |
| IFF | International Freight Forwarders (various locations) |
| IFF | International Fencing Federation |
| IFF | Inter-Faith Forum |
| IFF | Intergovernmental Forum on Forests |
| IFF | Information Flow Framework |
| IFF | Interrupt Flip Flop |
| IFF | Industrial Funding Fee |
| IFF | Instituttet for Fremtidsforskning (Danish: Institute for Future Studies) |
| IFF | Italian Fusion Festival (Dublin, Ireland) |
| IFF | Institut für Festkörperforschung (German: Institute for Solid State Research) |
| IFF | Iraq Freedom Fund |
| IFF | Indice Di Funzionalità Fluviale (Italian: River Functionality Index) |
| IFF | Inverness Film Fans (Scotland, UK) |
| IFF | Institut für Fertigteiltechnik (German: Institute of Precast Technology) |
| IFF | Intrastate Funding Formula |
| IFF | Illegal Foreign Fisher (Australia) |
| IFF | Issued for Fabrication |
| IFF | Information Flow Framework Language |
| IFF | International Flying Farmers |
| IFF | Interferon Fibroblast |