| Acronym | Definition |
|---|
| TTI | Texas Transportation Institute |
| TTI | Thurlby Thandar Instruments (UK) |
| TTI | Transmission Time Interval |
| TTI | Techtronic Industries Co., Ltd. (Hong Kong) |
| TTI | Thoracic Trauma Index |
| TTI | Travel Time Index |
| TTI | Travel Technology Initiative |
| TTI | Traffic and Traveller Information |
| TTI | Technology Transfer Initiative |
| TTI | Technology Transfer Institute |
| TTI | Time Temperature Integrator |
| TTI | Trail Trace Identifier |
| TTI | Time-Temperature Index |
| TTI | Total Totals Index (meteorology, severe weather forecasting) |
| TTI | Tactical Traffic Image |
| TTI | Terminal Translation Initialization |
| TTI | Transmit Terminal Identification (fax) |
| TTI | Trigger Time Interpolator |
| TTI | Training and Treatment Innovations, Inc. (Oxford, MI) |
| TTI | Tech Trans International |
| TTI | Tampa Technical Institute |
| TTI | Trusted Time Infrastructure |
| TTI | Tactical Target Illustration |
| TTI | Transaction Technologies, Incorporated |
| TTI | Technology Transfer Injection |
| TTI | Test Target Insertion |
| TTI | Teacher Telephone Interview (behavioral science) |
| TTI | Transit Time Isolator |
| TTI | Tilted Transverse Isotropic (seismic processing) |
| TTI | Transportable Theater Injection (satellite terminal) |
| TTI | Traveling Ticket Inspector (UK railways) |
| TTI | Time To Intercept/Impact |
| TTI | TEAM TESOL institute (Calgary, Alberta, Canada) |
| TTI | TEMPEST Technologies, Inc. |
| TTI | Travel Trade Italia |
| TTI | Transparent Technologies, Inc. (Lawrenceville, GA) |
| TTI | Travel and Transportation Industry |
| TTI | Telecom Technologies, Inc. (Eagan, MN) |
| TTI | Travel and Tourism Industry |
| TTI | Teaching Translation & Interpreting (Conference) |
| TTI | Ten Thousand Islands (island chain; Florida) |
| TTI | Total Translation, Inc. (est. 1994; Florida) |
| TTI | Tourism, Trade and Investment |