- DTSI stands for Direction des Technologies et des Systèmes d’Information (French: Directorate of Technology and Information Systems)
- DTSI stands for Digital Theater Systems, Inc. (stock symbol)
- DTSI stands for Digital Twin Spark Ignition
- DTSI stands for Defense Trade Security Initiative
- DTSI stands for Data Technology Services, Inc. (Colorado)
- DTSI stands for DataTel Solutions, Inc. (San Antonio, Texas)
- DTSI stands for Datron/Transco Systems Incorporated
DTSI