| Abbreviation | Definition |
|---|---|
| IEST | Institute of Environmental Science and Technology |
| IET | Institute for Environmental Toxicology |
| IET | Institute of Environmental Technology |
| IETA | Insulation and Environmental Training Agency |
| IETC | International Environmental Technology Centre |
| IETP | India Energy Training Program |
| IETP | Innovative Energy Technologies Program |
| IETP | Integrated Environmental Target Plan |
| IETP | Interdisciplinary Environmental Toxicology Program |
| IETP | International Energy Transition Plan |
| IEVPC | International Earthquake and Volcano Prediction Center |
| IFEM | Institute for Environmental Medicine |
| IFM | Integrated Flood Management |
| IFSA | International Forestry Students Association |
| IGBS | International Green Building Standard |
| IGEC | Index Of Global Environmental Change |
| IGEL | Institute for Georgia Environmental Leadership |
| IGES | Institute For Global Environmental Strategies |
| IHMM | Institute of Hazardous Materials Management |
| IHSB | Inactive Hazardous Sites Branch |