MTS is an operating system for IBM System/360 and its successors that was developed jointly by the following institutions:
- University of Michigan
- Wayne State University
- Simon Fraser University
- University of Alberta
- University of British Columbia
- Rensselaer Polytechnic Institute
- Durham University
- University of Newcastle-upon-Tyne
MTS doesn't implement directories, but there is a de facto two-tier grouping of files owing to the inclusion in a file's name of its owner's four-character MTS callsign.