| Acronym | Definition |
|---|
| FEI | Financial Executives International |
| FEI | Federation Equestre Internationale (French: International Federation for Equestrian sport) |
| FEI | Federal Executive Institute |
| FEI | Front End of Innovation |
| FEI | Financial Executives Institute |
| FEI | Fonds Europeen d'Investissement (French: European Investment Fund) |
| FEI | Fondo Europeo per gli Investimenti (Italian: European Investment Fund) |
| FEI | Frequency Electronics Inc. |
| FEI | Faculdade de Engenharia Industrial |
| FEI | Federal Employer Identification Number |
| FEI | Federation of the Electronics Industry (UK trade association) |
| FEI | Financial Engines, Inc. |
| FEI | Foreign Earned Income |
| FEI | Falange Española Independiente |
| FEI | Federation of Electronic Industries |
| FEI | For Everyone's Information |
| FEI | Free Estradiol Index (hormones) |
| FEI | Federal Electoral Institute (Election Bureau of Mexico) |
| FEI | Firing Error Indicator |
| FEI | Frequency Error Indicator |
| FEI | Fully Electronic Ignition |
| FEI | Final Energy Intensity |
| FEI | Facilities Engineering Items |
| FEI | Flight Engineer Instructor |
| FEI | Functionally Emulative Increment |
| FEI | Force Effectiveness Indicator |
| FEI | Final Earning Indicator (pension-related calculations) |
| FEI | Faculty of Electrical Engineering and Information Technology (Slovakia) |
| FEI | Fargo Electronics, Inc. (Eden Prairie, MN) |