| Acronym | Definition |
|---|
| TLS | Transport Layer Security |
| TLS | Timor Leste (East Timor ISO code) |
| TLS | Times Literary Supplement |
| TLS | Thread Local Storage |
| TLS | Transparent LAN Service |
| TLS | Total Least Squares |
| TLS | Typed Letter Signed (autographs) |
| TLS | Tumor Lysis Syndrome |
| TLS | Transaction Layer Security |
| TLS | The Last Supper |
| TLS | Tunable Laser Source |
| TLS | Through Life Support |
| TLS | Transponder Landing System |
| TLS | The Last Samurai (movie) |
| TLS | Trinity Lutheran School |
| TLS | Top Level Specification |
| TLS | Target LAN Server |
| TLS | Taiwan Light Source |
| TLS | Tekniska Litteratursällskapet (Swedish Society for Technical Documentation) |
| TLS | Toulouse, France - Blagnac (Airport Code) |
| TLS | Triple Link Suspension |
| TLS | Top Level School (USMC) |
| TLS | Third Level Support |
| TLS | Transaction Level Security |
| TLS | Teclas Locos Salvatruchos (street gang) |
| TLS | Terminology and Lexical Semantics (International Workshop) |
| TLS | Total Logistics Support |
| TLS | Thermal Laser Stimulation |
| TLS | Time Line Sheet |
| TLS | Transport LAN Service (US West) |
| TLS | Transmitter Location Systems, LLC |
| TLS | Tactical Logistics Systems |
| TLS | Text Library System (Financial Planning Consultants, Inc.) |
| TLS | Transformed Least Squares |
| TLS | Tactical Landing System |
| TLS | Turbo Lycoming Sabre (aircraft engine) |
| TLS | Thesaurus & Linguistic Integrated System (IBM) |
| TLS | Table of shared Locked States |
| TLS | Two-Layer Spreading |
| TLS | Training-Leader Development-Soldier Support |
| TLS | Tactical Landing Strip |
| TLS | The Logan School (Denver, Colorado) |
| TLS | Trimmed Leaf Size (printing/publishing) |
| TLS | Translocated in Liposarcoma-associated protein |
| TLS | Theater Logistics Station |
| TLS | Transmission-Line Stamp |
| TLS | Transfer-Line Spill |
| TLS | Trans-cowl Locking System (Pratt & Whitney) |
| TLS | Transmit Level Sensor |
| TLS | Time-Line Summary |
| TLS | Trzy Literowy Skrót (Polish: three letter acronym) |
| TLS | Triple Lead Sheath |
| TLS | Tons of Liquid Steel |
| TLS | Total Logistics Support (Navy) |