| Abbreviation | Definition |
|---|---|
| IESO | Indoor Environmental Standards Organization |
| IESS | Ingeniería Especializada en Sistemas de Seguridad |
| IET | Institution of Engineering and Technology |
| IETA | Idaho Education Technology Association |
| IETA | Inland Empire Taxpayers Association |
| IETA | Institutional Equity Traders Association |
| IETA | International ECP (External Counter Pulsation) Therapists Association |
| IETA | International Emissions Trading Association |
| IETD | Institute of Educational Training and Development |
| IETE | Intitution of Electronics and Telecommunication Engineers |
| IETF | Internet Engineering Task Force |
| IFA | Inshore Fishing Association |
| IFA | Institute of Financial Accountants |
| IFA | International Federation of Aromatherapists |
| IFA | International Franchise Association |
| IFA | Internet Football Association |
| IFAH | International Federation for Animal Health |
| IFAP | International Federation of Agricultural Producers |
| IFCC | International Federation of Clinical Chemistry |
| IFCI | Industrial Finance Corporation of India |