| Acronym | Meaning |
| TSL | Thermally Stimulated Luminescence |
| TSLLE | Thermospray Liquid-liquid Extraction |
| TSLOO2 | Thermal Stability At Low Oxygen |
| TSLP | Thymic Stromal Lymphopoietin |
| TSM | Total Suspended Material |
| TSM | Thickness Shear Mode |
| TSME | Two-state Molecular Expansion (method In Collisions Calcn.) |
| TSMG | Top-seeded Melt Growth |
| TSMR | Thickness-shear-mode Resonator |
| TSMS | Thermospray Mass Spectrometry |
| TSNA | Tobacco-specific Nitrosamines |
| TSNIGRI | Research Center Of The Institute For Geol. Exploration Of Base And Precious Metals (Russia) |
| TSO | Time Sharing Option |
| TSP | Total Suspended Particles |
| TSPA | Total System Performance Assessment |
| TSQMS | Triple-stage Quadrupole Mass Spectrometry |
| TSR | Thermal Shock Resistance |
| TSS | Total Suspended Solids |
| TSSMS | Time Sharing Service Management System |
| TST | Transition State Theory |
| TST-CEQ | Transition State Theory-collinear Exact Quantum (method For Reactive Collisions) |
| TSW | Torsional Spin Wave (type Of Hartree-Fock Wave Function) |
| TTFA | Target Transformation Factor Analysis |
| TTHM | Total Trihalomethane |
| TTI | Time-temperature Integrator |
| TTL | Transistor-transistor Logic |
| TTLC | Total Threshold Limit Concentration |
| TTLW | Through-transmission Laser Welding |
| TTN | Technology Transfer Network |
| TTO | Transient Tracers In The Ocean |
| TTP | Thrombotic Thrombocytopenic Purpura |
| TTP | Tocopherol Transfer Protein |
| TTS | T Tauri Star |
| TTSS | Tropospheric Trace Species Sounder |
| TTSS | Type III Secretion System |
| TTU | Transportable Treatment Unit |
| TTVD | Trap-to-trap Vacuum Distillation |
| TUES | Tubingen Ultraviolet Echelle Spectrometer |
| TUNEL | Terminal Deoxynucleotidyl Transferase-mediated DUTP Nick End-labeling |
| TURA | Toxics Use Reduction Act 1989 |
| TVA | Tennessee Valley Authority |
| TVC | Thermal Vapor Compression |
| TVC | Total Viable Count |
| TVD | Total Variation Diminishing |
| TVOC | Total Volatile Organic Compounds |
| TVS | Transient Voltage Suppressor |
| TVS | Total Volatile Solids |
| TVS | Triangular Voltage Sweep |
| TWA | Time-weighted Average Limit |
| TWC | Three-Way Catalyst(s) |