| Acronym | Definition |
|---|
| EFS | Encrypted File System (Microsoft Windows 2000) |
| EFS | Event Free Survival (survival rates in clinical trials) |
| EFS | Evangeliska Fosterlandsstiftelsen (Sweden) |
| EFS | Electronic Filing System |
| EFS | European Federation of Sexology |
| EFS | Enterprise File Services (HP) |
| EFS | Expeditionary Fighter Squadron |
| EFS | Encryption File System (Intel) |
| EFS | Error Free Seconds (percentage) |
| EFS | Embedded File System |
| EFS | Electric Field Stimulation |
| EFS | English for Foreign Students |
| EFS | Electric Field Strength |
| EFS | Environment Friends Society |
| EFS | Economic Farm Surplus (farming productivity) |
| EFS | Ensemble Forecast System |
| EFS | Emperor of the Fading Suns (computer game) |
| EFS | Enhanced Flight Screening |
| EFS | Export Facilitation Scheme (Australian government) |
| EFS | End of Frame Sequence |
| EFS | Electronic Form System |
| EFS | External File System |
| EFS | Engineering Feasibility Study |
| EFS | Electric Funstuff (band & software company) |
| EFS | Escape From Samsara |
| EFS | Enterprise File Sharing |
| EFS | Effective Field Size |
| EFS | Enhanced Fujita Scale (tornado strength) |
| EFS | Environmental Feasibility Study |
| EFS | Emergency Feedwater System |
| EFS | Edwards, Faust, & Smith (Maine accounting firm) |
| EFS | Electronic Firing Switch |
| EFS | Electronic Filing Systems, Inc. |
| EFS | Essential Fire Support |
| EFS | Earth-Fixed System |
| EFS | Elastomeric Firestop (construction) |
| EFS | Emergency Feeding Service |
| EFS | Electrical Feeder System |
| EFS | Extended Fuel System |
| EFS | Electric Field-induced Spectra |
| EFS | Encrypting Firewall System |
| EFS | Extended Function Set |
| EFS | External Focus Subassembly |
| EFS | Equal Frequency Separation |
| EFS | Expert Finding Systems |
| EFS | Engineering Functional Specification |