| M+J | Mabey & Johnson 
| Others |
| M.J | Master of Journalism
| Others |
| M/J | Middle (School) / Junior (High)
| Others |
| M/J | Middle School/ Junior High
| Others |
| MJ | Madeira Jewelers
| Others |
| MJ | Madhukar Jalan
| Others |
| MJ | Magic Jack
| Others |
| MJ | Magic Johnson
| Others |
| MJ | Magical Journeys
| Others |
| MJ | Magnificent Job
| Others |
| MJ | Major Amendment
| Others |
| MJ | Major Jerkoff
| Others |
| MJ | Mamma Jamma
| Others |
| MJ | Man Jam
| Others |
| MJ | Manufacturers' Junction Railway
| Others |
| MJ | Manufacturers' Junction Railway Company
| Others |
| MJ | Mara Jade
| Others |
| MJ | Marc Jacobs
| Others |
| MJ | Margaret Jane
| Others |
| MJ | Margo Jill
| Others |
| MJ | Maria Jane
| Others |
| MJ | Maria Jose
| Others |
| MJ | Marine Jet
| Others |
| MJ | Mark Jacob
| Others |
| MJ | Mark Johnson
| Others |
| MJ | Martha Jean
| Others |
| MJ | Martin Jarvis
| Others |
| MJ | Martin John
| Others |
| MJ | Martin Josh
| Others |
| MJ | Marvel Junior
| Others |
| MJ | Marvin Jubilee
| Others |
| MJ | Mary Jane
| Others |
| MJ | Mary Jayne
| Others |
| MJ | Mary Jean
| Others |
| MJ | Mary Jeanne
| Others |
| MJ | Mary Joy
| Others |
| MJ | Mass of Jupiter
| Others |
| MJ | Master of Jurisprudence
| Others |
| MJ | Matthew James
| Others |
| MJ | Matthew Johnson
| Others |
| MJ | Matthew Justin
| Others |
| MJ | Mattie Johnson
| Others |
| MJ | Max Jones, jazz musician
| Others |
| MJ | Max Junior
| Others |
| MJ | Maynard James
| Others |
| MJ | Maynard Junior
| Others |
| MJ | Mechanical Joint
| Others |
| MJ | Media Java
| Others |
| MJ | Mega Joule
| Others |
| MJ | Melanie Joy
| Others |
| MJ | Mellisa Joy
| Others |
| MJ | Mental Jacker
| Others |
| MJ | Meowy Jealous
| Others |
| MJ | Meredith Jayne
| Others |
| MJ | Meridith Johnson
| Others |
| MJ | Metal Jacket
| Others |
| MJ | Michael Jackson
| Others |
| MJ | Michael Jacksonpic
| Others |
| MJ | Michael James
| Others |
| MJ | Michael Jason
| Others |
| MJ | Michael John
| Others |
| MJ | Michael Jordan
| Others |
| MJ | Michael Joseph
| Others |
| MJ | Michelle Jones
| Others |
| MJ | Middle Joy
| Others |
| MJ | Midnight Junior
| Others |
| MJ | Migaloo Jr
| Others |
| MJ | Mighty Jack
| Others |
| MJ | Mikaela Jade
| Others |
| MJ | Mike Joseph
| Others |
| MJ | MilliJoules
| Others |
| MJ | Min Jung
| Others |
| MJ | Minecraft Joules
| Others |
| MJ | Mini Java
| Others |
| MJ | Ministerio de Justicia
| Others |
| MJ | Mischievous Jellybean
| Others |
| MJ | Miserable And Jealous
| Others |
| MJ | Miss Jackson
| Others |
| MJ | Missy Jo
| Others |
| MJ | Mo Jazz
| Others |
| MJ | Monkey Jehovah
| Others |
| MJ | Moose Jaw
| Others |
| MJ | More Jazz
| Others |
| MJ | Morty Jeff
| Others |
| MJ | Mother Jenny
| Others |
| MJ | Multi Jurisdictional
| Others |
| MJ | Multimedia Journalist
| Others |
| MJ | Mumbo Jumbo
| Others |
| MJ | Musikalischer Jugendfreund
| Others |
| MJ | Myoclonic Jerks epilepsy
| Others |
| MJ | Mystic Jin
| Others |
| MJ | Mythical Journeys
| Others |