| Acronym | Definition |
|---|
| MJ | Michael Jackson (entertainer) |
| MJ | Michael Jordan |
| MJ | Magic Johnson |
| MJ | Mary-Jane (slang for marijuana) |
| MJ | Marijuana |
| MJ | Mary Jane (Watson/Watson-Parker; Spiderman character) |
| MJ | Mint Julep (drink) |
| MJ | Mick Jagger (Rolling Stones member) |
| MJ | Ministerio da Justica (Brazil) |
| MJ | Metal Jacket |
| MJ | Mah-Jong (game) |
| MJ | Mechanical Joint |
| MJ | Magic Jack |
| MJ | Michael Johnson (Olympic sprinter) |
| MJ | Megajoules |
| MJ | Monster Jam |
| MJ | Military Justice |
| MJ | Methyl Jasmonate |
| MJ | Millijoules |
| MJ | Military Judge |
| MJ | Minecraft Joules (energy unit; Buildcraft machines) |
| MJ | Mara Jade (Star Wars character) |
| MJ | Mark Joyner (internet marketing) |
| MJ | Modular Jack |
| MJ | Municipal Journal |
| MJ | Mango Juice |
| MJ | Maître du Jeu (French: Game Master) |
| MJ | Master Jack (slang for Master Corporal, Canadian Forces) |
| MJ | Master of Jurisprudence |
| MJ | Military Jurisdiction |
| MJ | Merge Join |
| MJ | Mark Jindrak (wrestler) |
| MJ | Master in Journalism |
| MJ | Madame Josephine (Australia) |
| MJ | Manitoba Judgments |
| MJ | Ministerul Justiþiei (Romania) |
| MJ | Male Joint (decision makers) |
| MJ | Mucho Joviality |