| Abbreviation | Definition |
|---|---|
| IESC | Integrated Electrical Services Company |
| IESC | Investment Evaluative Services Corporation |
| IESCO | Islamabad Electric Supply Company, LTD. |
| IESF | International Executive Search Federation |
| IESG | Integrity Electrical Services Group |
| IESI | Innovative Engineering Solutions Inc |
| IESI | Integrated Environmental Services, Inc. |
| IESI | International Enviroguard Systems Inc |
| IESL | Innovative ERP Solutions Ltd |
| IESN | Indiana Energy Services Network |
| IESO | Independent Electricity System Operator |
| IESS | Innovative Electronic Service Solutions |
| IESS | Inter-city Envelope Settlement Service |
| IESS | Internet Entrepreneurs Support Service |
| IESS | Invictus Environmental Safety Solutions |
| IEST | IWS Executive Search Team |
| IETA | Insurance Education & Training Associates, L.L.C. |
| IETB | Information Exchange Technology Branch |
| IETC | In Extremis Theater Company |
| IETC | Innovative Engineering Inc. |