MMJ

MMJ may refer to:
 * Medical marijuana, cannabis prescribed by physicians for their patients
 * MMJ (band), Filipino singing duo
 * Modified Modular Jack, a six-pin modular connector used by Digital Equipment Corporation on their computers and peripherals.
 * Moscow Mathematical Journal, a quarterly international academic journal published by the Independent University of Moscow
 * Multimedia journalism
 * My Morning Jacket, an American rock band
 * The IATA airport code of Matsumoto Airport in Matsumoto, Nagano Prefecture, Japan
 * The ISO 639-3 identifier code for the Majhwar language