EFSS

EFSS may refer to:


 * Enterprise file synchronization and sharing (enterprise file sync and share), software to securely share documents
 * Edgefield Secondary School, Punggol, Singapore
 * M327 Expeditionary Fire Support System (mortar), see List of crew-served weapons of the U.S. Armed Forces
 * M1163 Expeditionary Fire Support System (jeep), see List of currently active United States military land vehicles
 * LAV Expeditionary Fire Support System (armored car), see List of vehicles of the United States Marine Corps