| Acronym | Definition |
|---|
| ITSI | It Services Industry |
| ITSI | Innovative Technical Solutions Inc (Walnut Creek, CA) |
| ITSI | Infrastructure Training and Safety Institute (Texas) |
| ITSI | Intelligent Transportation Systems Institute (University of Minnesota) |
| ITSI | Information Technology Systems Implementation |
| ITSI | Information Technology Systems, Inc. |
| ITSI | Individual TETRA (Terrestrial Trunked Radio) Subscriber Identity (telecommunications) |
| ITSI | Information Technology Standards Institute |
| ITSI | Information Technology Solutions International, Inc. (Philippines) |