| Acronym | Definition |
|---|
| ETSI | European Telecommunications Standards Institute (France) |
| ETSI | European Telecommunications Standards Institute |
| ETSI | Ente Turistico Sociale Italiano (Italian: Italian Social Tourist Organization) |
| ETSI | European Telecoms Standards Institute (EU; Sophia-Antipolis Cedex, France) |
| ETSI | European Therapy Studies Institute (UK; est. 1992) |
| ETSI | Euroopa Telekommunikatsiooni Standardite Instituut (Estonian: European Telecommunications Standards Institute) |
| ETSI | Electronic Technology Systems Inc. (Natrona Heights, PA) |