MJ may refer to:
Mary Ottilie "M. J." Jennings Hegar (née Vonstein; born 1976) is an American Air Force veteran, businesswoman, and teacher.
Mj Rodriguez (born January 7, 1991; sometimes capitalized as MJ Rodriguez) is an American actress and singer.
Mjolnir () is a fictional mythical weapon appearing in American comic books published by Marvel Comics.
Monique Jacqueline Williams-Jenkins is an American professional wrestler currently signed to WWE performing in their developmental terriory NXT.
mjunction services limited is a 50:50 joint venture of two Indian steel conglomerate – the Steel Authority of India Ltd (SAIL) and Tata Steel.
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.