Demography includes such measures as population density and distribution, ethnicity, educational levels, public health metrics, fertility, economic status, religious affiliation, and other characteristics of the populace.

Its urban population—principally in greater Bangkok—was 45.7 percent of the total population in 2010 according to National Economic and Social Development Board (NESDB).

Accurate statistics are difficult to arrive at, as millions of Thai migrate from rural areas to cities, then return to their place of origin to help with seasonal field work.

Even though Thailand has one of the better social security systems in Asia, the increasing population of elderly people is a challenge for the country.

[2][3] Life expectancy has risen, a reflection of Thailand's efforts to implement effective public health policies.

An aggressive public education campaign begun in the early-1990s reduced the number of new HIV infections from 150,000 to under 10,000 annually.

[8] Although the UN classifies the birth and death registration of the National Statistics Office as incomplete the figures below clearly show the decreasing fertility in Thailand since the end of the 1950s.

In its report to the United Nations for the International Convention on the Elimination of All Forms of Racial Discrimination, the Thai government officially recognized 62 ethnic communities.

[24] Thailand's report to the UN provided population numbers for mountain peoples and ethnic communities in the northeast.

In descending order, the largest (equal to or greater than 400,000) are: Thailand's Ministry of Social Development and Human Security's 2015 Master Plan for the Development of Ethnic Groups in Thailand 2015–2017[26] omitted the larger, ethnoregional ethnic communities, including the Central Thai majority; it therefore covers only 9.7% of the population.

The vast majority of the Isan people, one-third of Thailand's population, are of ethnic Lao[25] with some belonging to the Khmer minority.

In more recent years the Isan people began mixing with the rest of the nation as urbanization and mobility increase.

Myanmar's numerous ethnic wars between the army and tribes who speak more than 40 languages and control large fiefdoms or states, has led to waves of immigrants seeking refuge or work in Thailand.

[30] Some 180,000 Cambodians were said to have left Thailand post-coup due to crackdown rumors, indicating government figures were an under count.

Malay- and Yawi-speaking Muslims of the south are another significant minority group (2.3 percent), yet there are a substantial number of ethnic Malays who speak only Thai.

[citation needed] Thailand is also home to more than 200,000 foreigners—retirees, extended tourists, and workers from, for example, Europe, North America, and elsewhere.

[33] The following table shows first languages in Thailand with 400,000 or more speakers according to the Royal Thai Government's 2011 Country Report to the Committee Responsible for the International Convention on the Elimination of All Forms of Racial Discrimination.

The government permits religious diversity, and other major religions are represented, though there is much social tension, especially in the Muslim south.

[40] As of March 2018[update], Thai government data showed that over 770,900 Cambodian migrants, meaning five percent of the total population of Cambodia, currently live in Thailand.

[41] Laotians are particularly numerous considering the small size of Laos' population, about seven million, due to the lack of a language barrier.