Which country does Wikipedia call the world's most populous Muslim-majority country? Indonesia.
Indonesia holds this distinction because Muslims make up about 87% of its population, representing roughly 244 million people. That is the world's largest Muslim population within a single country, even though Indonesia is not located in the Middle East.
Islam spread through the Indonesian archipelago largely via maritime trade, Muslim merchants, religious teachers, and Islamic sultanates. Muslim communities became established especially from the 13th and 14th centuries, while earlier Hindu-Buddhist kingdoms such as Srivijaya and Majapahit had shaped the region's culture.
A common mix-up is Pakistan or Bangladesh, both of which are also Muslim-majority countries with very large Muslim populations. Indonesia remains larger by total Muslim population. Indonesia is religiously diverse: Christianity is significant in several eastern provinces, Hinduism is strongly associated with Bali, and Buddhism and Confucian traditions are present among some communities.