The Lao (Lao: ລາວ, Isan: ลาว, IPA: láːw) is an ethnic subgroup of Tai/Dai in Southeast Asia.

The etymology of the word Lao is uncertain, although it may be related to tribes known as the Ai Lao (Lao: ອ້າຽລາວ, Isan: อ้ายลาว, Chinese: 哀牢; pinyin: Āiláo, Vietnamese: ai lao) who appear in Han Dynasty records in China and Vietnam as a people of what is now Yunan Province. Tribes descended from the Ai Lao included the Tai tribes that migrated to Southeast Asia. The English word Laotian, used interchangeably with Lao in most contexts, comes from French laotien/laotienne. The Lao people, like many other Tai peoples also refer to themselves as Tai (Lao: ໄທ, Isan: ไท, IPA: tʰáj) and more specifically Tai Lao (ໄທລາວ, ไทลาว). In Thailand, the local Lao people are differentiated from the Lao of Laos and by the Thais by the term Thai Isan (Lao: ໄທຍ໌ອີສານ, Isan: ไทยอีสาน, IPA: i: să:n), a Sanskrit-derived term meaning northeast, but 'Lao' is still used.

According to a shared legend amongst various Tai tribes, a possibly mythical king, Khun Borom Rachathiriat (ຂຸນບໍຣົມຣາຊາທິຣາດ, ขุนบรมราชาธิราช, [kʰǔn bɔ̄ː lóm láː sáː tʰī lâːt]) of Mueang Thaen (ເມືອງແຖນ, เมืองแถน, [mɯ́əŋ tʰɛ̌ːn]) (modern-day Điện Biên Phủ) begot several sons that settled and ruled other mueang, or city-states, across South-East Asia and southern China. Descended from ancient peoples known to the Chinese as the Yue and the Ai Lao, the Tai tribes began migrating into South-East Asia by the beginning of the 1st millennium, but large-scale migrations took place between the 7th and 13th centuries AD, especially from what is now Sipsongbanna, Yunnan Province and Guangxi. The reasons for Tai migration include pressures from Han Chinese expansion, Mongol invasions, suitable land for wet rice cultivation and the fall of states such as Nanzhao that the Tais inhabited.

Below is a list of Lao people (persons from Laos, or of Lao descent).

The Khmu ( /kəˈmuː/; also spelled Khamu or Kemu; Khammu or Khơ Mú in Vietnam; Lao: ຂະມຸ [kʰámū]; Thai: ขมุ) is one of the largest ethnic groups based in northern Laos. They can also be found in Burma, southwest China (in the Sipsong Panna in Yunnan province), Thailand, Vietnam, and Richmond, California, where they are an officially recognized ethnic group. In the People's Republic of China, however, they are not given official recognition as a separate ethnic group, and are instead placed under the broad category undistinguished ethnic groups.

The Khmu (also referred to as Khamu, Kammu or Kemu) were the indigenous inhabitants of northern Laos. There are more than 500,000 Khmu around the world, with populations of 450,000 in Laos, 43,000 in Vietnam, 10,000 in Thailand, 10,000 in China, and 8,000 in the United States.^{[citation needed]} The Khmu of Laos reside mainly within the Luang Prabang and Xieng Khouang Provinces. The Khmu of Thailand are clustered near the Thailand-Laos border. Most Khmu villages are isolated, and only slowly receiving electricity. In many areas the Khmu live alongside the Hmong and other regional minority ethnic groups. A large number of Khmu live in Richmond, California, having come as refugees from the Vietnam War. California is home to both the Khmu National Federation, Inc., and the Kmhmu Catholic National Center. Most Khmu in Thailand arrived recently from Laos and Vietnam as refugees, also around the outset of the Vietnam War. The Khmu, however, are closely related to the Mlabri, the indigenous yellow leaf people of Thailand.

The Thai people, or formerly Siamese, are the main ethnic group of Thailand and are part of the larger Tai ethnolinguistic peoples found in Thailand and adjacent countries in Southeast Asia as well as southern China. Their language is the Thai language, which is classified as part of the Tai–Kadai family of languages, and the majority of Thai are followers of Theravada Buddhism. The term Thai people may also refer to the population of Thailand in general, and not only to ethnic Thais. Today, "Thai people" usually includes Central and Southern Thai (Siamese proper), Northern Thai (Lanna) and Isan people (strictly speaking Western Lao).^{[citation needed]}

There have been many theories proposing the origin of the Tai people, especially the association of the Tai people with the Kingdom of Nanzhao that has been proved to be invalid. Linguistic studies suggested that the origin of the Tai people lies around the Chinese Province of Guangxi, where the Zhuang people are still a majority. The ancient Tai people should be the part of Chinese Nanyue or "southern barbarians". The Qin dynasty founded Guangdong in 241 BC, initiating the successive waves of Chinese migrations from the north for hundred years to come.