MSSB
| Acronym | Definition |
|---|---|
| MSSB | Morgan Stanley Smith Barney LLC (finance) |
| MSSB | Mechanical Services Switch Board (electrical power) |
| MSSB | Modified Statutory Solvency Basis |
| MSSB | M Shanghai String Band (Brooklyn, NY) |
| MSSB | Metropolitan Separate School Board (Toronto Catholic district) |
| MSSB | Maple Story Social Board (GameFAQs message board) |
| MSSB | My Social Stories Book (teaching aid; book) |