Model UN was first introduced to Japan in 1983 by Sadako Ogata (former UN High Commissioner for Refugees). MUN activities then gradually spread across Japan, conducted now in various universities. There are currently over 700 students conducting MUN activities in Japan; to list some, students range from University of Tokyo, Waseda University, Keio University, Sophia University, Kyoto University to Osaka University. With its over 30 years of history, Japanese MUN graduates are now leading wide range of careers including international organizations, Japanese ministries, financial sectors, IT companies, media, higher educational institutions and NGOs.

Currently, Japan Model United Nations (JMUN, an umbrella organization managing MUN activities and conferences in Japan) holds three other conferences apart from AJMUN (Kansai MUN in August, Kyushu Summer Session in September, Hokuriku MUN in November). Also, it is responsible for training and sending selected Japanese delegates to NMUN (National MUN in New York). JCK (Japan China Korea) Youth Forum and Global Classrooms (MUN for high school students) are other examples that show how MUN activities are widespread across Japan. In recent years, increasing number of high school students or even company leaders enjoy MUN activities for its educational values.