| Abbreviation | Definition |
|---|---|
| UOR | Undulating Oceanographic Recorder |
| UOR | Uniform Officer Record |
| UOS | UCAV Operational System |
| UOTC | University Officer Training Corps (UK) |
| UP&TT | Unit Personnel and Tonnage Table |
| UPAS | Unit Performance Assessment System |
| UPD | Underwater Propulsion Device |
| UPDF | Uganda People's Defence Force |
| UPDF | United Planet Defence Force |
| UPE | User Portability Extensions |
| UPH | Unaccompanied Personnel Housing |
| UPK | Universal Puller Kit |
| UPLR | Uniform Packaging and Labeling Regulation |
| UPRA | Ukrainian People's Revolutionary Army |
| UPRN | Unique Property Reference Number |
| UPS | Un-interruptable Power Supply |
| UPS | Unusual Points Situation |
| UPT | Undergraduate Pilot Training |
| UPT | Unit Proficiency Training |
| UPT | Uptake |