The foreign minister replaces Canada's Michaelle Jean, who had sought re-election for the top job at the International Organization of Francophonie.
The decision was announced Friday by the organization and by Armenian Prime Minister Nikol Pashinian at a summit of member countries in the Armenian capital of Yerevan.
Mushikiwabo promised to work to spread the French language and boost employment opportunities for youth in the organization's member states.
The group has 54 member states and 30 associate or observer members, representing more than 900 million people, mostly in Africa.
French President Emmanuel Macron had backed Mushikiwabo's candidacy.
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.