Buddhism is the largest-religion in Thailand, followed by around 93.4% of the country's population. By sheer numbers, it has the world's largest Buddhist population followed by China and Myanmar, with more than 64 million Buddhists. The Theravada branch is practiced by most Buddhists and shares many similarities with Sri Lankan Buddhism. Buddhism in Thailand has also become integrated with Hinduism from millennia of Indian influence, and Chinese religions from the large Thai Chinese population. Buddhist temples in Thailand are characterized by tall golden stupas, and the Buddhist architecture of Thailand is similar to that in other Southeast Asian countries, particularly Cambodia and Laos, with which Thailand shares cultural and historical heritages. Thailand, Cambodia, Myanmar, Sri Lanka and Laos are countries with Theravada Buddhist majorities.
Buddhism is believed to have come to what is now Thailand as early as the 3rd century BCE, in the time of the Indian Emperor Ashoka. Since then, Buddhism has played a significant role in Thai culture and society. Buddhism and the Thai monarchy have often been intertwined, with Thai kings historically seen as the main patrons of Buddhism in Thailand. Although politics and religion were generally separated for most of Thai history, Buddhism's connection to the Thai state would increase in the middle of the 19th century following the reforms of King Mongkut that would lead to the development of a royally-backed sect of Buddhism and increased centralization of the Thai sangha under the state, with state control over Buddhism increasing further after the 2014 coup d'état.