Islam is currently the fastest-growing religion in the world, according to a new study by the Pew Research Center analyzing global religious demographics from 2010 to 2020. The research shows that Muslims experienced the largest increase in numbers, outpacing all other faith groups combined, largely due to high birth rates and population growth in predominantly Muslim regions.
The report, titled Pew’s Global Religious Landscape, is the second edition of the Center’s in-depth analysis of worldwide religious affiliation trends. It reveals that the global Muslim population grew by 347 million people over the ten-year period, while Christianity, despite increasing by 122 million members, saw a decline in its share of the global population.
“Most of the Muslim growth comes from natural population increase,” said Conrad Hackett, a senior demographer at Pew. “It’s not about conversion, but simply that more Muslims are being born than are dying.”
By contrast, Christianity, which remains the largest religion globally with 2.3 billion followers (about 29% of the world’s population), is seeing its share decrease, especially in traditionally Christian regions such as Europe, North America, and Oceania. This decline is largely due to people leaving the faith in adulthood a trend called religious disaffiliation.
The study, based on 2,700 data sources from 201 countries, including censuses and demographic surveys, also looked at factors like fertility, mortality, and age distribution. It found that Muslims are heavily concentrated in regions with rapid population growth, such as:
- Middle East-North Africa, where they make up 94.2% of the population.
- Sub-Saharan Africa, where they represent 33%.
- The Asia-Pacific region, home to the largest Muslim population, saw a 16.2% increase.
Meanwhile, the religiously unaffiliated often referred to as “nones” — have become the third largest group globally, making up 24.2% of the population. This group has grown significantly in Western nations where many people raised as Christians no longer identify with any religion. For example:
- In North America, “nones” rose by 13 percentage points to 30.2%.
- In Europe, they increased by 6.6 points, reaching 25.3%.
The Asia-Pacific region houses 78% of the world’s unaffiliated population, with China alone accounting for 67% of them. However, measuring religiosity in China is complex, as many engage in spiritual practices without claiming a specific religious identity.
Buddhism is the only major religion that declined in total numbers, shrinking by 19 million people, largely due to disaffiliation in East Asia. However, the study notes that this doesn’t fully reflect the cultural and spiritual influence of Buddhism, since many practitioners do not formally identify as Buddhists.
Hindus, who represent 14.9% of the global population, experienced significant growth, especially due to migration:
- A 62% increase in the Middle East-North Africa region.
- A 55% rise in North America. India remains home to 95% of the world’s Hindu population.
The Jewish population, the smallest religious group covered in the study, grew modestly by 6%, from 14 million to 15 million between 2010 and 2020. Jews make up just 0.2% of the global population, with 45.9% residing in Israel the highest concentration in any one country.
This report is also notable for being Pew’s first to track religious switching examining how individuals move away from the religion of their upbringing. Data from 117 countries shows that Christianity has been particularly affected, with many adults raised as Christians no longer identifying with the faith.
The study highlights a rapidly shifting global religious landscape shaped by birth rates, migration, and evolving personal beliefs a trend likely to continue shaping societies around the world in the decades to come.
