| Abbreviation | Definition |
|---|---|
| MU | Musicians' Union |
| MUA | Maritime Union of Australia |
| MUAA | Miami Union Adventist Academy |
| MUB | Memorial Union Board |
| MUBE | Malta Union of Bank Employees |
| MUBS | Monash Union of Berwick Students |
| MUCG | Management Union Consultative Group |
| MUF | Morris Union Federation |
| MUGA | Memorial Union Games Area |
| MUH | Milch Union Hocheifel |
| MUHS | Middlebury Union High School |
| MUI | Maritime Union of India |
| MUJ | Madras Union of Journalists |
| MULS | Minnesota Union List of Serials |
| MUM | Maintenance of Union Membership |
| MUNZ | Maritime Union of New Zealand |
| MUP | Medical Union Pharmaceuticals |
| MUP | Missouri Union Presbytery |
| MUPC | Memorial Union Program Council |
| MUS | Montecito Union School |