| Acronym | Definition |
|---|
| TPI | Teeth Per Inch |
| TPI | Titleist Performance Institute (golf) |
| TPI | Treads per Inch (tires) |
| TPI | Tuned Port Injection |
| TPI | Threads Per Inch |
| TPI | Third Party Insurance |
| TPI | Tribunal Pénal International (French: International Criminal Tribunal; Netherlands) |
| TPI | Tracks Per Inch |
| TPI | Travel Planners International (Maitland, FL) |
| TPI | Transport Information Item |
| TPI | Travel Professionals International (Canada) |
| TPI | Transpacific Industries Group Ltd. (Australia) |
| TPI | Truss Plate Institute |
| TPI | Test Process Improvement |
| TPI | Third Party Interface (software) |
| TPI | Total Personal Income |
| TPI | Turkish Patent Institute (Turkey) |
| TPI | Turfgrass Producers International |
| TPI | Third-Party Inspection |
| TPI | Tillotson-Pearson, Inc. (now TPI Composites) |
| TPI | Trigger Point Injection |
| TPI | Thermoplastic Polyimide |
| TPI | Tribunale Penale Internazionale (International Court of Justice, The Netherlands) |
| TPI | Timber Products Inspection (Conyers, GA; est. 1969) |
| TPI | Turning Point, Inc. (Safety Harbor, FL) |
| TPI | Turns Per Inch (machining and welding) |
| TPI | Target Position Indicator (US Navy) |
| TPI | Twisted Pair Interface (electronic components) |
| TPI | Third-Party Intermediaries |
| TPI | Tender Price Index |
| TPI | Total Positive Income |
| TPI | Two Person Integrity |
| TPI | Théatre de la Photographie et de l'Image (French: Theater of Photography and Image) |
| TPI | Titre au Porteur Identifiable (French: Identifiable Title Bearer; finance) |
| TPI | Tons Per Inch Immersion |
| TPI | Technology Partnership Initiative (UK) |
| TPI | Tap Position Indicator (EMCO; electronics) |
| TPI | Team Première Infanterie (French: Team First Infantry; online gaming clan) |
| TPI | Terminal Phase Initiation |
| TPI | Transistorized Pointless Ignition (motorcycles) |
| TPI | Tsutsunaka Plastic Industry (Japan) |
| TPI | Technical Proposal Instructions |
| TPI | Test Program Instruction |
| TPI | Trading Partner Interchange (e-business software) |
| TPI | Telecom Plus International |
| TPI | Throttle Position Indicator (automobile electronic sensor) |
| TPI | Time-Provider Interface |
| TPI | Total Performance Indicator |
| TPI | Tableau Pédagogique Interactif (French: Interactive Learning Table) |
| TPI | Technical Points of Interest |
| TPI | Technology Policy International |
| TPI | Telecom Performance Index |
| TPI | Tail-Plane Incidence |
| TPI | Tanzania Pharmaceutical Industry Ltd |
| TPI | Tradepoint International (World Trade and Industry Organization) |
| TPI | Telemarketing Professionals, Inc. |
| TPI | Transportability Problem Item |
| TPI | Tilted Plate Interceptor (separates oil from contaminated water - oil refineries) |
| TPI | Temporary Program of Instruction |
| TPI | Test Planning Integration |
| TPI | Technical/Technician Proficiency Inspection |
| TPI | TRADOC Procurement Instruction |
| TPI | Transport Service Programmers Interface |