Both the majority Kinh people and the country's 53 ethnic minority groups derive from three great language families - the Austro-Asiatic, the Austronesian and the Sino-Tibetan.

The majority Việt language (tiếng Việt) is one of approximately 150 languages belonging to the Austro-Asian language family. However, the classification of tiếng Việt and its upland counterpart Mường within that language family is still the subject of academic debate - some scholars argue that it should be classified as part of the Mon-Khmer language group, while others (including most Vietnamese linguists) maintain that it should be categorised as a separate language group within the Austro-Asian language family, on the same level as Mon-Khmer, Asli, Munda and Nicobar.

Branches of the Mon-Khmer language group represented in Việt Nam include Eastern Mon-Khmer (Khơ-me), Bahnar (Ba-na, Brâu, Gié-Triêng, Chơ-ro, Cơ-ho, Hrê, Mạ, Sre-M'nông, Rơ-măm, Xơ-đăng and Xtiêng), Katu (Bru-Vân Kiều, Ca-tu, Ta-ôi), Khmu (Kháng, Khơ-mú, Ơ-đu, Xinh-mun) and Mang (Mảng). The Khơ-me (equivalent to the Khmer of Cambodia) constitute the sixth largest ethnic people in the country and are widely settled throughout the Mekong Delta provinces of the south. The great majority of the other Môn-Khmer ethnicities are settled in the central and southern-central highlands region bordering Cambodia and southern Laos; notable exceptions to this rule are the Khơ-mú, Kháng, Mảng and Xinh-mun, all of whom reside in the mountainous north west.

Three branches of the Austro-Thai linguistic family are represented in Việt Nam - Austronesian (Malay-Polynesian), Hmong-Mien and Tai-Kadai.

The Austronesian or Malay-Polynesian language family is represented by five of Việt Nam's ethnic minority groups – the Chăm, the Chu-ru, the Ê-đê, the Gia-rai and the Ra-glai – all of whom hail from an Achinese-Chamic sub-sub-branch of Sundic and are to be found in south-central Việt Nam. Perhaps best-known of these are the Chăm (or Chàm), now settled in the southern coastal provinces of Bình Thuận, Ninh Thuận, Khánh Hòa, Phú Yên and Bình Định, whose ancestors founded the ancient kingdom of Champa. However, more numerous today are their neighbours the Ra-glai and the Chu-ru, and their central highland cousins the Ê-đê of Đắc Lắc province and the Gia-rai of Gia Lai and Kon Tum provinces.

The Hmong-Mien group is believed to have migrated from southern China into Việt Nam, Laos and northern Thailand only over the last 300 years, and all representatives in Việt Nam of its two constituent branches, the Hmong and the Mien, are settled exclusively in the north of the country. Of the four Hmong language branches found throughout the wider region, three are represented in Việt Nam. The White H'mông (H'mông trắng), the Flower or Variegated H'mông (H'mông hoa) and the Blue or Green H’mông (H’mông xanh) hail from the Chuanqiandian language group, the Black H'mông (H'mông đen) from the Qiandong language group and the Red H'mông (H'mông đỏ) from the Xiangxi language group. The Mien group is represented in Viet Nam by the Dao (Yao), all of whom are classified (like their cousins in neighbouring Thailand and Laos) as part of the Iu Mien language group. However, significant dialectical differences exist between major Dao sub-groups such as the Black Dao (Dao đen), the Coin Dao (Dai tiền), the Red Dao (Dao đỏ), the Tight-trousered Dao (Dao quần chẹt) and the White-trousered Dao (Dao quần trắng).

The H'mông and the Dao are Việt Nam's eighth and ninth largest ethnic group respectively. The H'mông are settled widely across the north of the country but particularly in Sơn La, Điện Biên, Lai Châu, Lào Cai, Tuyên Quang, Yên Bái, Hà Giang and Cao Bằng Provinces. The Dao are also found widely throughout the mountainous north of Viet Nam, with major pockets of settlement in Hòa Bình, Sơn La, Điện Biên, Lai Châu, Lào Cai, Tuyên Quang, Thái Nguyên, Yên Bái, Hà Giang, Bắc Cạn, Cao Bằng and Lạng Sơn Provinces.

The Tai-Kadai group comprises two branches – Kadai or Kam-Tai (Cờ Lao, La Chí, La Ha and Pu Péo) and Tày-Thái (Bố Y, Giáy, Lào, Lừ, Nùng, Sán Chay, Tày and Black/White Thai). Common ancestors of both branches are known to have migrated from southern China in large numbers during the first millennium CE. Some travelled as far as modern-day Laos and Thailand where they went on to lay the foundations for the powerful kingdoms of Lan Xang (Tày-Thái) and Sukhothai (Kadai), while others chose to settle en route in the northern mountains of Việt Nam. Today the Tày (north east Việt Nam), the Black and White Thái (north-west Việt Nam) and the Nùng (north east Việt Nam) constitute respectively the second, third and seventh largest ethnic groups in the country after the Kinh.

The Sino-Tibetan linguistic family is represented in Việt Nam by two groups. The Hán (Sinitic) language group incorporates the Yunnanese or south west Mandarin-speaking Hoa, Ngái and Sán Dìu ethnicities; and the Lolo-Burmish language group incorporates the Lolo-speaking Cống, Hà Nhì, La Hủ, Lô Lô, Phù Lá and Si La ethnicities. The Hoa or ethnic Chinese constitute Việt Nam's fifth largest ethnic group, who are nowadays found mainly in Hồ Chí Minh City and the surrounding Mekong Delta provinces, though scattered rural Hoa settlements may also be found in many other parts of the country. All other Sino-Tibetan ethnicities are settled exclusively in the north of Việt Nam.