| Acronym | Definition |
|---|
| ISFF | International Short Film Festival |
| ISFF | International Student Film Festival |
| ISFF | Iraqi Security Forces Fund |
| ISFF | International Science Film Festival |
| ISFF | Integrated Surface Flux Facility |
| ISFF | Intergraph Standard File Format |
| ISFF | International Student Football Federation |
| ISFF | International Science Fiction Federation |
| ISFF | Irina Slutskaya Fan Forum |
| ISFF | Incredibly Strange Film Festival |
| ISFF | Independent School Fees Fund (UK) |
| ISFF | Idaho Spent Fuel Facility |
| ISFF | International Surrealist Film Festival |
| ISFF | Interior Structural Firefighter |
| ISFF | ICSI Speech File Format |
| ISFF | Inspector of Salmon and Freshwater Fisheries (UK) |
| ISFF | International Sahara Film Festival |