FNSI
| Acronym | Definition |
|---|---|
| FNSI | Federazione Nazionale Stampa Italiana |
| FNSI | Finding of No Significant Impact |
| FNSI | Federación Nacional de Sindicatos Independientes (Spanish: National Federation of Independent Trade Unions; Mexico) |
| FNSI | First Nations Statistical Institute (Canada) |
| FNSI | Fiber Network Solutions, Inc. (internet provider) |