MJ may refer to:
Mj Rodriguez (born January 7, 1991; sometimes capitalized as MJ Rodriguez) is an American actress and singer.
Mary Jennings Hegar (née von Stein; born 1976) is an American politician, Air Force veteran, businesswoman, and teacher.
Mjolnir, known more formally as Mjölnir () is a fictional mythical weapon appearing in American comic books published by Marvel Comics.
MJ Cole (born Matthew James Firth Coleman, 9 August 1973) is an English DJ, record producer, musician and remixer.
Mjøsa is Norway's largest lake, as well as one of the deepest lakes in Norway and in Europe. It is the fourth-deepest lake in Norway.
MJ is a jukebox musical with music and lyrics by Michael Jackson, and a book by Lynn Nottage.The original production of MJ is scheduled to premiere on Broadway in mid-2020, with direction by Christopher Wheeldon.
Mjällby Allmänna Idrottsförening, also known simply as Mjällby AIF, Mjällby or (especially locally) MAIF, is a Swedish professional football club based in Hällevik.