Islam experienced the fastest growth among the world’s major religions in the decade leading up to 2020, according to new estimates from the Pew Research Center.

During this period, the global Muslim population surged by 347 million, reaching approximately 2.0 billion. This growth outpaced that of every other religious group, solidifying Islam’s position as the second-largest religion globally, following Christianity.

In contrast, the number of Christians grew by 122 million, totaling 2.3 billion by 2020. Notably, Buddhists were the only major group to see a decline in absolute numbers, decreasing by 19 million to 324 million.

The study spanned 201 countries and territories, covering 99.98% of the global population, and focused on seven religious categories: Christians, Muslims, Hindus, Buddhists, Jews, followers of other religions, and the religiously unaffiliated.

Muslim population growth during this decade exceeded the combined growth of all non-Muslim groups, which totaled 248 million. Remarkably, the increase in Muslims alone was greater than the entire global Buddhist population in 2020.

This rapid expansion has narrowed the population gap between Muslims and Christians.

In 2010, Muslims represented 23.9% of the global population compared to Christians at 30.6%. By 2020, those figures had shifted to 25.6% for Muslims and 28.8% for Christians. One key factor behind the slower growth of Christianity is high rates of religious disaffiliation.

Why Is the Muslim Population Growing So Quickly?

Pew Research Center reported that the primary drivers of Muslim population growth are demographic. Muslims tend to be younger and have higher fertility rates than adherents of other religions.

Between 2015 and 2020, Muslim women had an average of 2.9 children, compared to 2.2 for non-Muslim women. Additionally, the median age of Muslims in 2020 was 24, nine years younger than the global non-Muslim median age of 33.

Religious conversion played a minimal role in this growth. Survey data from 117 countries between 2008 and 2024 indicate that about 1% of those raised as Muslims leave the faith. However, this is roughly offset by an equivalent number of people converting to Islam.

Where Do Most Muslims Live?

In 2020, the largest number of Muslims resided in the Asia-Pacific region (1.2 billion), followed by the Middle East and North Africa (414 million), and Sub-Saharan Africa (369 million). Although Europe and North America have much smaller Muslim populations, these communities

experienced significantly faster growth compared to their non-Muslim counterparts during the decade.

Muslims made up the highest share of the population in the Middle East and North Africa, comprising 94% of the region’s inhabitants. However, despite its strong association with Islam, this region accounted for only about 20% of the world’s Muslim population, Pew Research Center reported.

The countries with the largest Muslim populations in 2020 were outside the Middle East:

Indonesia: 239 million
Pakistan: 227 million
India: 213 million
Bangladesh: 151 million

Globally, Muslims formed the majority in 53 countries and territories as of 2020.