UN finds child grooms, followed by Nicaragua and Madagascar.
An estimated 115 million boys and men worldwide were married as children, Unicef research has found.
Of those, one in five (23 million) became child grooms before the age of 15.
Unicef analysed data from 82 countries and found child marriage among boys was prevalent in a range of countries around the world, including those in sub-Saharan Africa, Latin America and the Caribbean, South Asia, East Asia and the Pacific.
“Marriage steals childhood,” said Henrietta Fore, Unicef’s executive director. “Child grooms are forced to take on adult responsibilities for which they may not be ready.
“Early marriage brings early fatherhood, and with it added pressure to provide for a family, cutting short education and job opportunities.”
The Central African Republic had the highest prevalence of child marriage among males (28 per cent), followed by Nicaragua (19 per cent) and Madagascar (13 per cent).
The latest estimate brings the total number of child brides and grooms worldwide to 765 million.
Unicef said girls remain disproportionately affected.
One in five young women aged 20 to 24-years-old were married before their 18th birthday, compared to one in 30 young men.
The charity said little research exists on the prevalence, causes and impacts of child marriage among boys compared to child marriage among girls.
It said children most at risk of child marriage were found to come from the poorest households, live in rural areas and have little to no education.
“As we mark the 30th anniversary of the adoption of the Convention on the Rights of the Child, we need to remember that marrying boys and girls off while they are still children runs counter to the rights enshrined in the Convention,” said Fore.
“Through further research, investment and empowerment, we can end this violation.”