| Acronym | Definition |
|---|
| TPI | Tracks Per Inch |
| TPI | Teeth Per Inch |
| TPI | Threads Per Inch |
| TPI | Test Process Improvement |
| TPI | Truss Plate Institute |
| TPI | Tuned Port Injection |
| TPI | Turfgrass Producers International |
| TPI | Tribunale Penale Internazionale (International Court of Justice, The Netherlands) |
| TPI | Turns Per Inch (machining and welding) |
| TPI | Third-Party Inspection |
| TPI | Thermoplastic Polyimide |
| TPI | Third-Party Intermediaries |
| TPI | Trigger Point Injection |
| TPI | Two Person Integrity |
| TPI | Total Positive Income |
| TPI | Tender Price Index |
| TPI | Technology Partnership Initiative (UK) |
| TPI | Tons Per Inch Immersion |
| TPI | Tap Position Indicator (EMCO; electronics) |
| TPI | Terminal Phase Initiation |
| TPI | Technical Proposal Instructions |
| TPI | Test Program Instruction |
| TPI | Throttle Position Indicator (automobile electronic sensor) |
| TPI | Time-Provider Interface |
| TPI | Telecom Plus International |
| TPI | Total Performance Indicator |
| TPI | Technical Points of Interest |
| TPI | Technology Policy International |
| TPI | Telecom Performance Index |
| TPI | Tail-Plane Incidence |
| TPI | Tanzania Pharmaceutical Industry Ltd |
| TPI | Telemarketing Professionals, Inc. |
| TPI | Tradepoint International (World Trade and Industry Organization) |
| TPI | Transportability Problem Item |
| TPI | Technical/Technician Proficiency Inspection |
| TPI | Test Planning Integration |
| TPI | TRADOC Procurement Instruction |
| TPI | Tilted Plate Interceptor (separates oil from contaminated water - oil refineries) |
| TPI | Temporary Program of Instruction |
| TPI | Transport Service Programmers Interface |