Thailand's population is relatively homogeneous. More than 85% speak a dialect of Thai and share a common culture. This core population includes the central Thai (33.7% of the population, including Bangkok), Northeastern Thai (34.2%), northern Thai (18.8%), and southern Thai (13.3%).

The language of the central Thai population is the language taught in schools and used in government. Several other small Thai-speaking groups include the Shan, Lue, and Phutai.

Up to 12% of Thai are of significant Chinese heritage, but the Sino-Thai community is the best integrated in Southeast Asia. Malay-speaking Muslims of the south comprise another significant minority group (2.3%). Other groups include the Khmer; the Mon, who are substantially assimilated with the Thai; and the Vietnamese. Smaller mountain-dwelling tribes, such as the Hmong and Mein, as well as the Karen, number about 788,024.

The population is mostly rural, concentrated in the rice-growing areas of the central, northeastern, and northern regions. However, as Thailand continues to industrialize, its urban population--31.1% of total population, principally in the Bangkok area--is growing.

Thailand's highly successful government-sponsored family planning program has resulted in a dramatic decline in population growth from 3.1% in 1960 to around 1% today. Life expectancy also has risen, a positive reflection of Thailand's efforts at public health education. However, the AIDS epidemic has had a major impact on the Thai population. Today, over 700,000 Thais live with HIV or AIDS--approximately two percent of adult men and 1.5 percent of adult women. Each year until at least 2006, 30-50,000 Thais will die from AIDS-related causes. Ninety percent of them will be aged 20-24, the most productive sector of the workforce. The situation could have been worse; an aggressive public education campaign in the early 1990s reduced the number of new HIV infections from 150,000 to 25,000 annually.

The constitution mandates 12 years of free education, however, this is not provided universally. Education accounts for 19% of total government expenditures.

Theravada Buddhism is the official religion of Thailand and is the religion of about 95% of its people. The government permits religious diversity, and other major religions are represented. Spirit worship and animism are widely practiced.