| Abbreviation | Definition |
|---|---|
| RSGB | Russian Spetsnaz Guards Brigade |
| RSI | Rationalization, Standardization, and Interoperability |
| RSI | Resources, Screening, and Intelligence |
| RSIC | Redstone Scientific Information Center, Redstone Arsenal, AL |
| RSIS | Rotorcraft Systems Integrated Simulator |
| RSK | Risk |
| RSK | Ritter Survival Knife |
| RSL | Ready Service Locker |
| RSL | Retired Servicemen's League |
| RSL | Returned and Services League (of Australia) |
| RSLF | Royal Saudi Land Forces |
| RSM | Regimental Sergeant Major |
| RSME | Royal School of Military Engineering |
| RSN | Republic of Singapore Navy |
| RSN | Role Specialist Nation |
| RSNF | Royal Saudi Naval Force |
| RSO | Range Safety Officer |
| RSO | Reconnaissance and Surveillance Operation |
| RSO | Reconnaissance Systems Officer |
| RSO | Regional Security Officer |