| Acronym | Definition |
|---|
| ISF | International Softball Federation |
| ISF | Internal Security Forces (Lebanon) |
| ISF | Importer Security Filing |
| ISF | Impôt de Solidarité sur la Fortune (French: wealth tax) |
| ISF | Imaging Science Foundation |
| ISF | Ian Somerhalder Foundation (est. 2010) |
| ISF | Ingegneria Senza Frontiere (Italian: Engineers without Borders) |
| ISF | International Seed Federation (Switzerland) |
| ISF | Internal Service Fund (various organizations) |
| ISF | Informatici Senza Frontiere (Italian: Computers Without Borders) |
| ISF | Information Security Framework (various companies) |
| ISF | Information Security Forum (est. 1989) |
| ISF | Indexed Sequential File |
| ISF | Internet Security Framework |
| ISF | Incoming Signal Failure |
| ISF | Inter System Facilities |
| ISF | International Shipping Federation |
| ISF | Iraqi Security Force |
| ISF | Indian Staffing Federation (employment) |
| ISF | Institute for Sustainable Futures (Sydney, Australia) |
| ISF | Interstitial Fluid |
| ISF | Insofar |
| ISF | Illinois Service Federal (banking) |
| ISF | Initiative Sozialistisches Forum (German: Socialist Initiative Forum) |
| ISF | International Science Foundation |
| ISF | Israeli Special Forces |
| ISF | Insufficient Funds |
| ISF | India Social Forum (World Social Forum) |
| ISF | International Ski Federation |
| ISF | Institutt for Samfunnsmedisinske Fag (Norwegian: Department of Public Health) |
| ISF | Iowa State Fair |
| ISF | Information Systems Frontiers |
| ISF | International Sepsis Forum |
| ISF | Indian State Forces |
| ISF | International Snowboarding Federation |
| ISF | I Sådana Fall |
| ISF | Ingenieros Sin Fronteras (Spanish: Engineers Without Borders) |
| ISF | Integrated Social Forestry (Philippines) |
| ISF | International Song Festival |
| ISF | Industry Super Fund (Australia) |
| ISF | International Shinto Foundation |
| ISF | Information Security Foundation |
| ISF | Islamic Salvation Front |
| ISF | Industrial Space Facility |
| ISF | Imperial Smelting Furnace |
| ISF | Information Strike Force (Navy/Marine Corp Intranet; NMCI) |
| ISF | Interscholastic Surfing Federation (Carlsbad, CA) |
| ISF | Integrated Support Facility |
| ISF | Individual Share Future (finance) |
| ISF | Integrative Strategies Forum |
| ISF | International School Frankfurt |
| ISF | Information Systems Forum |
| ISF | Ingénierie Sans Frontières (French: Engineering Withouth Borders; Sherbrooke, Québec, Canada) |
| ISF | Industrial Share Fund |
| ISF | Investigator Site File |
| ISF | Ingénierie Sans Frontières (Engineers Without Borders) |
| ISF | Imperial Special Forces (gaming) |
| ISF | Institute of Soil Fertility (Netherlands) |
| ISF | Investigative Support & Forensics |
| ISF | International Society of Financiers, Inc. |
| ISF | Integration Support Facility |
| ISF | Import Service Fee |
| ISF | In Service Failure |
| ISF | Indian Standard Flat |
| ISF | Intelligence Support Facility |
| ISF | Integrated Support-Fielding |
| ISF | Infrastructure Support Facilities |
| ISF | Income Stabilization Fund |