A hill tribe is any one of around twenty ethnic groups living in Northern Thailand. Most of these groups also exist outside Thailand, but the term is most often used to refer to the Thai groups. The word "tribe" itself is somewhat inaccurate, as the groups have no leaders; the term “mountain people” is sometimes preferred although they do not all live in mountains.

The hill tribes together number approximately 550,000. Most of them migrated from Tibet, China, Burma or Laos in the 19th and 20th centuries. The main groups are the Yao, Karen (Thai Gariang), Akha (Thai Egaw), Lahu (Thai Musay) Hmong (Thai Meo) and Lisu (Thai Lisaw).

The Thai government has opposed some of the hill tribes’ agricultural practices, specifically the growing of opium and the use of slash and burn agriculture. Its campaigns against both of these have met with some success.

Many hill tribe people now make all or part of their living from the tourist industry, either by hosting trekkers or by selling handicrafts. The children in many of the tribes are often dressed in very colourful clothing, and wear valuable bangles and necklaces. Their headress is often bedecked with silver coins and other silver ornaments. Many of the children, even toddlers, smoke cheap cigarettes.