| EFSS | Early Fall School of Semiotics 
| Others |
| EFSS | Education Funding Spending Share
| Others |
| EFSS | Egyptian Fertility and Sterility Society
| Others |
| EFSS | Electronic Form Submission Service
| Others |
| EFSS | Endoscopic Frontal Sinus Surgery
| Others |
| EFSS | Engine Compartment Fire Suppression System
| Others |
| EFSS | Enterprise File Sharing and Synchronization
| Others |
| EFSS | Enterprise file sync and share
| Others |
| EFSS | Enterprise File Sync and Sharing
| Others |
| EFSS | Enterprise File Synchronisation and Sharing
| Others |
| EFSS | Enterprise File Synchronization and Sharing
| Others |
| EFSS | Enterprise File Syncing and Sharing
| Others |
| EFSS | Environmental Field Sampling Study
| Others |
| EFSS | Expeditionary Fire Support System
| Others |
| EFSS | Expeditionary Force Support Squadron
| Others |