FSE
- Fast Software Encryption
- Federation of European Scouting (disambiguation)
- Feline spongiform encephalopathy
- Ferrovie del Sud Est
- Fetal scalp electrode
- Finite-state entropy
- Finnish Sign Language
- Football Supporters Europe
- Franciscan Sisters of the Eucharist
- Frankfurt Stock Exchange
- Free surface effect
- Fremont Street Experience
- Fukuoka Stock Exchange
- Fung Seng Enterprises