NSSI
| Acronym | Definition |
|---|---|
| NSSI | Non-Suicidal Self-Injury (intentional self damage) |
| NSSI | National Social Security Institute (Bulgaria; pensions and benefits management) |
| NSSI | National Security Space Institute (formerly the Air Force Space Operations School) |
| NSSI | North Slope Science Initiative (Alaska) |
| NSSI | Navrátil Software System Information |
| NSSI | No Significant Schedule Impact |
| NSSI | Nuclear Safety/Security Inspection |