Mainland Thai culture is heavily influenced by Buddhism. However, unlike the Buddhist countries of East Asia, Thailand's Buddhists follow the Theravada school, which is arguably closer to its Indian roots and places a heavier emphasis on monasticism. Thai temples known as wats — resplendent with gold and easily identifiable with their ornate, multicolored, pointy roofs — are ubiquitous. Becoming an orange-robed monk for a short period, typically the three-month rainy season, is a common rite of passage for young Thai boys and men. That being said, there are also prominent Mahayana Buddhist temples, most of which were built in Chinese architectural styles to serve the ethnic Chinese community.

One pre-Buddhist tradition that still survives is the spirit house (ศาลพระภูมิ saan phraphuum), usually found at the corner of any house or business, which houses spirits so they don't enter the house and cause trouble. The grander the building, the larger the spirit house, and buildings placed in particularly unlucky spots may have very large ones. Perhaps the most famous spirit house in Thailand is the Erawan Shrine in Bangkok, which protects the Erawan Hotel (now the Grand Hyatt Erawan), built in 1956 on a former execution ground, and is now one of the busiest and most popular shrines in the city. It and several other popular shrines pay homage to Hindu deities. Hinduism was once the dominant religion in Thailand prior to the spread of Buddhism, and many traditional Thai arts continue to draw their inspiration from Hindu mythology.

Some traditional arts popular in Thailand include traditional Thai dancing and music, based on religious rituals and Court entertainment. There is a vibrant popular music scene with morlam and lukthung not at all overshadowed by Western style pop. Famously brutal Thai boxing (muay Thai), derived from the military training of Thai warriors, is undoubtedly the country's best known indigenous sport.

In addition to the mainland Thai culture, there are many other cultures in Thailand including those of the "hill tribes" in the northern mountainous regions of Thailand (e.g., Hmong, Karen, Lisu, Lahu, Akha), the southern Muslims, and indigenous island peoples of the Andaman Sea. The ethnic Chinese population has been largely assimilated into Thai culture, though vestiges of their Chinese heritage can still be found in Bangkok's Chinatown. The Chinese have, however, left a huge impact on Thailand's culinary scene, and many dishes of Chinese origin, such as noodles, roast pork and steamed buns, have been widely adopted and are now seen as an integral part of Thai cuisine. The Thai-Chinese can generally be divided into two groups: those that migrated to Thailand as traders and labourers during the 19th and early 20th centuries, who mainly came from Fujian, Guangdong or Hainan and settled in the larger cities like Bangkok, Hat Yai and Phuket; and some groups of Kuomintang soldiers who fled China in the aftermath of the Chinese Civil War, who mainly came from Yunnan and settled in remote mountain villages along the Burmese border like Mae Salong and Ban Rak Thai.