A 2014 Pew Research study found that the two countries with the most religious diversity (Singapore and Vietnam) are in Southeast Asia. At the same time, one of the least religiously diverse countries (Timor-Leste) is from the same region.
We map the largest religious group (by percentage of population) in each Southeast Asian country. Data for this map and article are from the US State Department's Religious Freedom Report (2022).
Islam, Buddhism and Christianity in Southeast Asia
Southeast Asian countries mostly follow one of the three major religions: Buddhism, Islam and Christianity.
Buddhism was first brought to the region by Indian and Chinese traders between the 1st and 3rd centuries. However, despite its early arrival, the religion accounts for around 35-38% of Southeast Asia's population, second only to Islam.
Here is a breakdown of the largest religious groups in Southeast Asian countries, along with their proportion of the population.
Note: Includes all sects and denominations. *Only 14% of Vietnam is religious, including 6% Christian, 5% Buddhist and 3% of other religions.
In Cambodia and Thailand, where more than 90% of the population is Buddhist, nine out of ten people surveyed by Pew Research said being Buddhist was important to their national identity. More than 70% of Cambodians also see Buddhism as an innate ethnicity.
Islam, meanwhile, arrived with Arab traders in the 7th century. More than 85% of Indonesia, the world's fourth most populous country, is Muslim, helping Islam become the majority religion throughout Southeast Asia.
Finally, European missionaries brought Christianity to the region in the 16th century. Most Christians in the region are Catholic. Indonesia has the highest number of Catholics (after the Philippines) of any country (despite being mostly Muslim).