| Abbreviation | Definition |
|---|---|
| MSSD | Manitou Springs School District |
| MSSD | Milan Special School District |
| MSSD | Minneapolis Special School District |
| MSSD | Missouri Schools for the Severely Disabled |
| MSSD | Model Secondary School for the Deaf |
| MSSL | Master of Science in School Leadership |
| MSSL | Middle School Sports League |
| MSSM | Maine School of Science and Mathematics |
| MSSM | Mount Sinai School of Medicine |
| MSSM | Mt Sinai School of Medicine |
| MSSN | Malawi School Solar Network |
| MSSN | Manchester Supplementary School Network |
| MSSP | Middle School Sports Program |
| MSSR | Moderated School Self Review |
| MSSS | Mikhyla and Scarlett's Sabbath School |
| MSST | Mathematics for Secondary School Teachers |
| MSST | Midtown School of Science and Technology |
| MST | Melbourne School of Theology |
| MSTA | Marsha Stern Talmudical Academy (Yeshiva University High School for Boys) |
| MSTA | Mill School and Technology Academy |