The country has an area of 198,000 square miles and a population of 64 million. According to the 2000 census, approximately 94 percent of the population is Buddhist and 5 percent is Muslim. Nongovernmental organizations (NGOs), academics, and religious groups claim 85 to 95 percent of the population is Theravada Buddhist and between 5 to 15 percent is Muslim. There are also small animist, Christian, Confucian, Hindu, Jewish, Sikh, and Taoist populations. According to the Religious Affairs Department (RAD), persons who do not profess a religious faith make up less than one percent of the population.
Theravada Buddhism is the dominant religion, although it is not an exclusive belief system, and most Thai Buddhists also incorporate Brahmin-Hindu and animist practices. The Buddhist clergy (Sangha) consists of two main schools: Mahanikaya and Dhammayuttika. The former is older and more prevalent within the monastic community than the latter, which grew out of a 19th-century reform movement led by King Mongkut (Rama IV). The same ecclesiastical hierarchy governs both groups.
Islam is the dominant religion in four of the five southernmost provinces, which border Malaysia. The majority of Muslims are ethnic Malay, but the Muslim population also includes descendants of immigrants from South Asia, China, Cambodia, and Indonesia. The RAD reported that there are 3,644 registered mosques in 67 provinces, of which 3,088 are located in the 14 southern provinces. Of those, 2,331 are located in the five southernmost provinces. There are 488 mosques in the 25 provinces of the central region, 42 in the 13 provinces of the northern region, and 26 in the 15 provinces of the northeastern region. According to the RAD, 99 percent of these mosques are associated with the Sunni branch of Islam. Shi'a mosques make up the remaining 1 percent and are not located in the south, but are in Bangkok and the provinces of Nakhon Sithammarat and Krabi. There are 38 Provincial Islamic Committees nationwide.
According to the 2000 census, there are an estimated 438,600 Christians in the country, constituting 0.7 percent of the population. While there are a number of denominations, the Government recognizes five Christian umbrella organizations: the Catholic Mission of Bangkok (Roman Catholic); the Church of Christ in Thailand (Protestant); the Evangelical Fellowship of Thailand (Protestant); Saha Christchak (Baptist); and the Seventh-day Adventists. The oldest of these groupings, the Church of Christ in Thailand (CCT), was formed in 1934 and claims 1,080 churches and 149,125 adherents. The Catholic Mission of Bangkok has 406 churches and 333,240 believers. The Evangelical Foundation of Thailand has 1,200 churches and approximately 150,000 believers. The Seventh-day Adventists have approximately 200 churches and 12,712 members, and the Saha Christchak Baptists report 95 churches and 10,531 followers.
According to a 2002 government survey, there are nine recognized tribal groups (chao khao), comprised of approximately 920,000 persons. These groups generally practice syncretistic forms of Buddhism, Christianity, Taoism, and spirit worship.
The Secretary-General of the Sikh Council of Thailand estimates that there are up to 30,000 Sikhs. Although there are 16 Sikh temples, only 10 or 11 are active.
According to RAD statistics and local Hindu organizations, there are an estimated 100,000 Hindus and nine Hindu temples.
The majority of ethnic Chinese and Vietnamese practice Mahayana or Theravada Buddhism. There are more than 750 Chinese and Vietnamese Mahayana Buddhist shrines and temples throughout the country. Included in this statistic are 20 Vietnamese temples, 17 Chinese temples, and 682 Chinese shrines that registered with the Ministry of Interior. Many ethnic Chinese, as well as members of the Mien hill tribe, practice forms of Taoism. Some ethnic Chinese also practice Christianity, mainly Protestantism.