| Abbreviation | Definition |
|---|---|
| MSI | Maharishi Sadashiva Isham |
| MSO | Management Services Officer |
| MSO | Medical Service Officer |
| MSO | Money Service Operator |
| MSP | Member of Scottish Parliament |
| MSPA | Member of the American Society of Pension Actuaries |
| MSR | Member Service Representative |
| MSW | Medical Social Worker |
| MSW | Mental Services Worker |
| MT | Man Thinker |
| MT | Master Taxidermist |
| MT | Master Trainer |
| MT | Medical Technologist |
| MT | Move Tutor |
| MTA | Medical Technical Assistant |
| MTIT | Mytxiisterif |
| MTM | Manufacturing Team Member |
| MTM | Master Technician Mercruiser |
| MTO | Management Training Officer |
| MTO | Manufacturing Technical Operations |