The report, compiled by UN's children agency UNICEF in partnership with Morocco's National Council for Human Rights and the Amane association, said girls under the age of 17 were the most affected, with 28,886 being married in 2013 alone.
Since 2004 the number of minors who were married in Morocco has risen by 91 percent, with the largest number of such unions taking place in rural areas, the report said yesterday.
More than 18,000 under-age marriages were registered in 2004 - against 35,152 in 2013.
Article 19 of Morocco's family code, adopted in 2004, sets the legal age for marriage at 18 although articles 20 and 21 provide loopholes.
Article 21 says the marriage of a minor is allowed if he or she obtains the consent of a legal guardian.