| Acronym | Definition |
|---|
| GTI | Gas Technology Institute |
| GTI | Global Taxonomy Initiative |
| GTI | Good Time Interval |
| GTI | Guelph Turfgrass Institute |
| GTI | Global Threat Intelligence |
| GTI | Green Theme International |
| GTI | Galway Technical Institute |
| GTI | Guilford Transportation Industries |
| GTI | Gordon Training International |
| GTI | Groundwater Technology Inc |
| GTI | Georgia Transportation Institute |
| GTI | Grand Touring Injection |
| GTI | Global Trade Information Services, Inc |
| GTI | Gires Tournois Interferometer |
| GTI | Ground Transport Interchange (airports) |
| GTI | Göteborgs Tekniska Institut (Swedish: The Technical Institute of Gothenburg) |
| GTI | German Travel International (German travel agency) |
| GTI | Global Title Indicator (SS7 SCCP) |
| GTI | Government Training Institute, Inc. (Idaho, USA) |
| GTI | Garantie de Temps d'Intervention (French: Guaranteed Response Time) |
| GTI | Group Travel Insurance |
| GTI | Government Technology International |
| GTI | Grounded Theory Institute (Mill Valley, CA, USA) |
| GTI | Ground Test Instrumentation |
| GTI | Group Term Insurance |
| GTI | Government Telecommunications, Incorporated |
| GTI | Groep Technische Installaties (Dutch company) |
| GTI | General Telemarketing International Inc (Denton, Texas) |
| GTI | GPS Timing Interfaces (Sprint) |
| GTI | Genotoxic Impurity |
| GTI | Ground Test Instruction (aircraft) |
| GTI | Global Temperature Increase (climate) |