JMJ may refer to: An abbreviation for the Holy Family (consisting of Jesus, Mary, and Joseph), printed by Christians on the top of letters and other places IATA code for Lancang Jingmai Airport Jam Master Jay, (1965–2002), American musician and rapper Jam Master Jay Records, an American record label Jean-Michel Jarre (born 1948), French composer and producer Justin Meldal-Johnsen (born 1970), American musician World Youth Day (French: , Spanish , Portuguese: )