Islam was the fastest-growing religion in the world during the decade leading up to 2020, according to estimates from the Pew Research Centre. 

From 2010 to 2020, the number of Muslims increased by 347 million people to 2.0 billion people. 

Muslims are the second-largest religious group in the world after Christians, but the gap is tightening. Christians grew by 122 million to 2.3 billion. 

During the past decade, the Muslim population increased by 347 million, which surpassed the combined growth of all non-Muslim religions (248 million.)

In fact, the growth of the Muslim population exceeded the entire number of Buddhists worldwide in 2020, which stood at 324 million. Buddhists were the only group in its analysis that shrank in absolute numbers by 19 million people.

“As a result of the rapid growth of the Muslim population, the gap between the global number of Muslims and Christians is shrinking,” said an article on the Pew Research Center. 

“In 2010, Muslims made up 23.9% of the world’s population and Christians accounted for 30.6%. By 2020, Muslims accounted for 25.6% and Christians 28.8%. Growth in the number of Christians was slowed by high rates of disaffiliation.”

Their estimates covered 201 countries and territories that are home to 99.98% of the world’s population. The research looked at Muslims, Christians, Hindus, Buddhists, Jews, adherents of all other religions, and people who do not identify with any religion. 

Reasons the global Muslim population grew quickly

According to the report, shifts in Muslim population size are mainly driven by demographic factors.

Muslims have more children and are younger, on average, than members of any other major religion, it said. 

“Based on data for the 2015-2020 period, we estimated a Muslim woman would have 2.9 children, on average, in her lifetime, compared with 2.2 children per non-Muslim woman. In 2020, the global median age for Muslims was nine years below the non-Muslim median (24 vs. 33),” said the Pew Research Center. 

Analysis of survey data from 117 countries and territories spanning 2008 to 2024 reveals that approximately 1% of individuals raised in Muslim households eventually leave Islam.

But this departure rate is balanced by a similar percentage of people converting to Islam.

The global distribution of Muslim populations reveals that the largest Muslim communities are located beyond the Middle East and North Africa region. 

Indonesia leads with 239 million Muslims, followed by Pakistan (227 million), India (213 million), and Bangladesh (151 million) as of 2020. 

Across the globe, Muslims constitute the majority of the population in 53 countries and territories.