GSI may refer to:
Science and technology
- Geotechnical seismic isolation
- Geological Strength Index
- Gonadosomatic Index
- UK Government Secure Intranet
- Grid Security Infrastructure, a computer networking specification
- "Global Systems Integrator", large managed technology services providers
- GS-I (Cellulose synthase (UDP-forming)), an enzyme
- Great Sea Interconnector
Businesses and organizations
Businesses
- Gemological Science International, gemstone identification/grading/appraisal services
- Geophysical Service Incorporated, an American petroleum exploration corporation
- Guangzhou Shipyard International, a Chinese state-owned shipbuilder
- GSI Commerce, now eBay Enterprise, an American e-commerce company
Scientific organizations
- GSI Helmholtz Centre for Heavy Ion Research, Germany
- Geographical Society of Ireland
- Geospatial Information Authority of Japan
- Geological Society of India
- Geological Survey of India
- Geological Survey of Ireland
Other organizations
- Global Security Initiative
- Gabinete de Segurança Institucional da Presidência da República (Institutional Security Bureau), Brazil
- Gustav Stresemann Institute, a German educational charity
Other uses
- Graduate student instructor, a teaching fellow at some US universities
- Grand-Santi Airport, French Guiana (IATA code GSI)
See also
- GSL (disambiguation)
- GS-1 (disambiguation), including GS1
- GS (disambiguation)
- GSIS (disambiguation)