| Acronym | Meaning |
| TRK | Track |
| TRK UP | Track Up |
| TRQ | Torque |
| TRR | Test Readiness Review |
| TRU | Test Replaceable (repairable) Unit |
| TRU | Transformer Rectifier Unit |
| TSA | Trainer Support Activity |
| TSA | Training Support Agent |
| TSEC | Tactical Speech Security Equipment |
| TSEC | Transmission Secure |
| TSEP | Tactical Signal Exploitation Program |
| TSI | Tactical Situation Indicator |
| TSOT | Trident Sonar Operator Trainer |
| TSR | Technical Software Review |
| TSR | Test Strategy Reports |
| TSS | Training System Software |
| TSSA | Training Systems Support Activity |
| TSTAS | Tailored Ship Training Availabilites |
| TT | Technology Transfer |
| TTACT | Table Top Aircrew Coordination Trainer |
| TTD | Technical Training Device (simulation System) |
| TTE | Technical Training Equipment (tactical/operational) |
| TTEL | Tools And Test Equipment List |
| TTF | Trident Training Facility |
| TTG | Trainer Test Group |
| TTGP | Tactical Training Group Pacific |
| TTL | Transistor Transistor Logic |
| TTP | Trainer Test Procedures |
| TTPRR | Trainer Test Procedures And Results Report (udi-t-25594) |
| TTRR | Trainer Test Results Report |
| TTSA | Trainer Tactical Software Activity |
| TTT | Team Tactics Trainer |
| TUE | Trainer Unique Equipment |
| TUNA | Tunable Attribute Display Sub-system |
| TURB | Trainer Update Review Board |
| TUSS | Trainer Unique Subsystem Units |
| TVIB | Turbine Vibration |
| TWCS | Through Water Communications System |
| TWG | Technical Working Group |
| TWT | Traveling Wave Tube |
| UART | Universal Asynchronous Receiver/transmitter |
| UAV | Unmanned Air Vehicle |
| UBA | Underwater Breathing Apparatus (mk 15) |
| UC | Update Code |
| UDATS | Diver Underwater Tv System |
| UDI | Unique Data Item |
| UE | User Equipment |
| UHF | Ultra High Frequency |
| UHF DAMA | Uhf Satellite Demand Assigned Multi-access |
| UI | Unit Of Issue |