| Abbreviation | Definition |
|---|---|
| MCS | Manhattan Country School |
| MCS | Maryknoll Convent School |
| MCS | Massena Central School |
| MCS | Memphis City Schools |
| MCS | Modesto City Schools |
| MCSA | McKinley Community School for Adults |
| MCSB | Monroe City School Board |
| MCSC | Merrillville Community School Corporation |
| MCSCC | Montague County Special Classes Coop |
| MCSD | Manatee County Sheriffs Department |
| MCSD | Merced City School District |
| MCSD | Mifflin County School District |
| MCSD | Monroe County School District |
| MCSD | Montrose County School District |
| MCSD | Muscogee County School District |
| MCSF | Maryville City Schools Foundation |
| MCSK | Military Collegiate School Khulna |
| MCSN | Maryland Charter School Network |
| MCSO | Multiple Charter School Organizations |
| MCSP | Military Collegiate School Phultala |