| Acronym | Definition |
|---|
| TLS | Transport Layer Security |
| TLS | Tulsa (Amtrak station code; Tulsa, OK) |
| TLS | Times Literary Supplement |
| TLS | Timor Leste (East Timor ISO code) |
| TLS | Terrestrial Laser Scanning (earth science) |
| TLS | Thread Local Storage |
| TLS | Typed Letter Signed (autographs) |
| TLS | Tumor Lysis Syndrome |
| TLS | Total Least Squares |
| TLS | Triple Link Suspension |
| TLS | Transparent LAN Service |
| TLS | Tunable Laser Source |
| TLS | Through Life Support |
| TLS | Transaction Layer Security |
| TLS | Trans Link Systems (Dutch joint venture) |
| TLS | The Last Supper |
| TLS | Trinity Lutheran School |
| TLS | Transmission Line Systems |
| TLS | Technical Library Supplement |
| TLS | Terminal Server Licensing |
| TLS | Three Letter Shortcut |
| TLS | Tax & Legal Services |
| TLS | Transperfect Legal Solutions (New York, NY) |
| TLS | Transponder Landing System |
| TLS | Top Level School (USMC) |
| TLS | Third Level Support |
| TLS | The Learning Station (band; Melbourne, FL) |
| TLS | Toyota Logistics Services (est. 1976; Toyota Motor Sales) |
| TLS | Thought Leadership Summit |
| TLS | The Last Samurai (movie) |
| TLS | Transaction Level Security |
| TLS | Target Level of Safety (aviation) |
| TLS | Tons of Liquid Steel |
| TLS | Text Library System (Financial Planning Consultants, Inc.) |
| TLS | Tactical Landing System |
| TLS | Total Logistics Support |
| TLS | Total Logistics Support (Navy) |
| TLS | Tekniska Litteratursällskapet (Swedish Society for Technical Documentation) |
| TLS | Top Level Specification |
| TLS | Target LAN Server |
| TLS | The Living Statues (band) |
| TLS | Taiwan Light Source |
| TLS | The Logan School (Denver, Colorado) |
| TLS | Tactical Logistics Systems |
| TLS | Transport LAN Service (US West) |
| TLS | Toulouse, France - Blagnac (Airport Code) |
| TLS | Teclas Locos Salvatruchos (Maryland; Mara Salvatrucha clique) |
| TLS | Tactical Laser System (Ace Combat; video game) |
| TLS | Terminology and Lexical Semantics (International Workshop) |
| TLS | Thermal Laser Stimulation |
| TLS | Time Line Sheet |
| TLS | Transmitter Location Systems, LLC |
| TLS | Timber Laminated Stringer |
| TLS | Thang Long Securities (Vietnam) |
| TLS | Transformed Least Squares |
| TLS | Turbo Lycoming Sabre (aircraft engine) |
| TLS | Table of shared Locked States |
| TLS | Thesaurus & Linguistic Integrated System (IBM) |
| TLS | Two-Layer Spreading |
| TLS | Tactical Landing Strip |
| TLS | Training-Leader Development-Soldier Support |
| TLS | Time Labor System |
| TLS | Trimmed Leaf Size (printing/publishing) |
| TLS | Theater Logistics Station |
| TLS | Translocated in Liposarcoma-associated protein |
| TLS | Transmission-Line Stamp |
| TLS | Transfer-Line Spill |
| TLS | Transmit Level Sensor |
| TLS | Trans-cowl Locking System (Pratt & Whitney) |
| TLS | Travel Leadership Summit |
| TLS | Time-Line Summary |
| TLS | Trzy Literowy Skrót (Polish: three letter acronym) |
| TLS | Triple Lead Sheath |