structural:reformatting, information:extraction
Ethnic groups

As of 2010, Thai people make up the majority of Thailand's population (95.9%). The remaining 4.1% of the population are Burmese (2.0%), others (1.3%), and unspecified (0.9%).

According to genetic research, the present-day Thai people were divided into three groups: the northern group (Khon Mueang) are closely related to the Tai ethnic groups in southern China, the northeastern group (Isan people) are mixed Tai and several Austroasiatic -speaking ethnic groups, while the central and southern groups (formerly called Siamese) strongly share genetic profiles with the Mon people.

According to the Royal Thai Government's 2011 Country Report to the UN Committee responsible for the International Convention for the Elimination of All Forms of Racial Discrimination, available from the Department of Rights and Liberties Promotion of the Thai Ministry of Justice, 62 ethnic communities are officially recognized in Thailand. Twenty million Central Thai (together with approximately 650,000 Khorat Thai) made up approximately 20,650,000 (34.1 per cent) of the state's population of 60,544,937 at the time of completion of the Mahidol University Ethnolinguistic Maps of Thailand data (1997).

The 2011 Thailand Country Report provides population numbers for mountain peoples ('hill tribes') and ethnic communities in the Northeast and is explicit about its main reliance on the Mahidol University Ethnolinguistic Maps of Thailand data. Thus, though over 3.288 million people in the Northeast alone could not be categorised, the population and percentages of other ethnic communities c. 1997 are known for all of Thailand and constitute minimum populations. In descending order, the largest (equal to or greater than 400,000) are a) 15,080,000 Lao (24.9 per cent) consisting of the Thai Lao (14 million) and other smaller Lao groups, namely the Thai Loei (400–500,000), Lao Lom (350,000), Lao Wiang/Klang (200,000), Lao Khrang (90,000), Lao Ngaew (30,000), and Lao Ti (10,000); b) six million Khon Muang (9.9 per cent, also called Northern Thais); c) 4.5 million Pak Tai (7.5 per cent, also called Southern Thais); d) 1.4 million Khmer Leu (2.3 per cent, also called Northern Khmer); e) 900,000 Malay (1.5%); f) 500,000 Nyaw (0.8 per cent); g) 470,000 Phu Thai (0.8 per cent); h) 400,000 Kuy/Kuay (also known as Suay) (0.7 per cent), and i) 350,000 Karen (0.6 per cent). Thai Chinese, those of significant Chinese heritage, are 14% of the population, while Thais with partial Chinese ancestry comprise up to 40% of the population. Thai Malays represent 3% of the population, with the remainder consisting of Mons, Khmers and various " hill tribes ".

Increasing numbers of migrants from neighbouring Myanmar, Laos, and Cambodia, as well as from Nepal and India, have pushed the total number of non-national residents to around 3.5 million as of 2009, up from an estimated 2 million in 2008. Some 41,000 Britons and 20,000 Australians live in Thailand.