| Acronym | Definition |
|---|
| IEF | Isoelectric Focusing (experiment) |
| IEF | International Energy Forum |
| IEF | Instituto de Estudios Fiscales (Spanish: Institute for Fiscal Studies) |
| IEF | Index of Economic Freedom (survey) |
| IEF | Information Engineering Facility |
| IEF | Internet Exchange File |
| IEF | Integrity Enhancement Facility |
| IEF | Image Exchange Format |
| IEF | Image File |
| IEF | International Eye Foundation |
| IEF | International Entrepreneurship Forum (est. 2000) |
| IEF | International Environment Forum |
| IEF | Investor Education Fund |
| IEF | International Energy Foundation |
| IEF | Implied Emission Factor |
| IEF | International Economy Freight (commerical carriage modality; FedEx) |
| IEF | Internet Education Foundation |
| IEF | International Energy Fund |
| IEF | IntelliLight Entrance Facility (Verizon Communications Inc.) |
| IEF | International Exhibitions Foundation |
| IEF | Initial Entry Forces |
| IEF | Integrity Enhancement Facility (computing) |
| IEF | Imaging Energy Filter |
| IEF | International Enterprise Forum |
| IEF | In-Transit Evacuation Facility |
| IEF | Integrated Evaluation Framework (US DoD) |