A 2014 Pew Research study found that two of the most religiously diverse countries (Singapore and Vietnam) are in Southeast Asia. At the same time one of the least religiously-diverse countries (Timor-Leste) is also from the same region.

We map out the largest religious group (by percentage of the population) in every Southeast Asian country.

Data for this map and article is sourced from the U.S. State Department’s Religious Freedom Report (2022).

Islam, Buddhism, and Christianity in Southeast Asia

Southeast Asian countries predominantly follow one of three major religions: Buddhism, Islam, and Christianity.

Buddhism arrived first in the region, between the 1st–3rd centuries, brought by Indian and Chinese traders. However, despite arriving first, the religion accounts for about 35-38% of the Southeast Asian population, second after Islam.

Here’s a breakdown of the largest religious group in each Southeast Asian country, along with the percentage of the population.

Note: Includes all denominations and sects. *Only 14% of Vietnam is religious, of which 6% is Christian, 5% Buddhist, and 3% other religions.

In Cambodia and Thailand, where over 90% of the population is Buddhist, nearly nine-in-ten people surveyed by Pew Research said being a Buddhist was important to their national identities. More than 70% Cambodians also see Buddhism as an ethnicity one is born into.

Meanwhile, Islam arrived in the 7th century, brought along with Arabian traders. More than 85% of Indonesia—the world’s fourth-most populous country—is Muslim, helping Islam become the majority religion of Southeast Asia as a whole.

Finally, European missionaries brought Christianity to the region in the 16th century. Most Christians in the region are Catholics. Indonesia (despite being predominantly Muslim) has the second-highest number of Catholics (after the Philippines) amongst the countries.