Đại Việt (大越, IPA: [ɗâjˀ vìət]; literally Great Việt), was a Vietnamese monarchy in eastern Mainland Southeast Asia from the 10th century AD to the early 19th century, centered around the region of present-day Hanoi. Its early name, Đại Cồ Việt, was established in 968 by the ruler Đinh Bộ Lĩnh after he ended the Anarchy of the 12 Warlords, until the beginning of the reign of Lý Thánh Tông (r. 1054–1072), the third emperor of the Lý dynasty. Đại Việt lasted until the reign of Gia Long (r. 1802–1820), the first emperor of the Nguyễn dynasty, when the name was changed to Việt Nam in 1804. Under rule of bilateral diplomacy with Imperial China, it was known as Principality of Giao Chỉ (chữ Hán: 交趾) (975–1164) and Kingdom of Annam (chữ Hán: 安南) (1164–1804) when Emperor Xiaozong of Song upgraded Đại Việt's status from principality to kingdom.

Đại Việt's history was divided into the rule of eight dynasties: Đinh (968–980), Early Lê (980–1009), Lý (1009–1226), Trần (1226–1400), Hồ (1400–1407), and Later Lê (1428–1789); the Mạc dynasty (1527–1677); and the short-lived Tây Sơn dynasty (1778–1802). It was briefly interrupted by the Hồ dynasty (1400–1407), which changed the country's name to Đại Ngu, and the Fourth Era of Northern Domination (1407–1427), when the region was administered as Jiaozhi by the Ming dynasty. Đại Việt's history can also be divided into two periods: the unified state, which lasted from the 960s to 1533, and the fragmented state, from 1533 to 1802, when there were more than one dynasty and several noble clans simultaneously ruling from their own domains. From the 13th to the 18th century, Đại Việt's borders expanded to encompass territory that resembled modern-day Vietnam, which lies along the South China Sea from the Gulf of Tonkin to the Gulf of Thailand.

Early Đại Việt emerged in the 960s as a hereditary monarchy, with Mahayana Buddhism as its state religion, and lasted for six centuries. From the 16th century onwards, it gradually weakened and decentralized into multiple sub-kingdoms and domains, ruled by either the Lê, Mạc, Trịnh, or Nguyễn families simultaneously. It was briefly unified by the Tây Sơn brothers in 1786, who divided it among themselves in 1787. After the Lê-Mạc war, followed by the Trịnh-Nguyễn War and the Tây Sơn wars that ended with a final Nguyễn victory and the destruction of the Tây Sơn dynasty, Đại Việt was reunified, ending 262 years of fragmentation with the founding of the Nguyễn dynasty in 1802. From 968 to 1804, Đại Việt flourished and acquired significant power in the region. The state slowly annexed Champa and Cambodia's territories, expanding Vietnamese territories to the south and west. The state of Đại Việt was the primary precursor to the country of Vietnam and the basis for its national historic and cultural identity.

The term Việt (Yue) (Chinese: 越; pinyin: Yuè; Cantonese Yale: Yuht; Wade–Giles: Yüeh; Vietnamese: Việt) in Early Middle Chinese was first written using the logograph "戉" for an axe (a homophone) in oracle bone and bronze inscriptions of the late Shang dynasty (c. 1200 BC), and later as "越". At the time, it may have referred to a people or chieftain to the northwest of the Shang, such as the Yuefang. According to Ye Wenxian (1990) and Wan (2013), the ethnonym of the Yuefang in northwestern China is not associated with that of the Baiyue in southeastern China. In the early 8th century BC, a tribe on the middle Yangtze was called the "Yangyue", a term later used for people further south. Between the 7th and 4th centuries BC, Yue/Việt referred to the state of Yue in the lower Yangtze basin and its people.

From the 3rd century BC on, the term was used for the non-Han Chinese populations of south and southwest China and northern Vietnam, with particular ethnic groups called Minyue, Ouyue, Luoyue (Vietnamese: Lạc Việt), etc., collectively referred to as the Baiyue (Chinese: 百越; pinyin: Bǎiyuè; Cantonese Yale: Baak Yuet; Vietnamese: Bách Việt; lit. 'Hundred Yue/Việt'). The term Baiyue (or Bách Việt) first appeared in the book Lüshi Chunqiu, compiled around 239 BC. At first, Yue referred to all peoples of the south that practiced un-Chinese slash-and-burn cultivation and lived in stilt houses, but this definition does not suggest that all Yue were the same and spoke the same language. They were loosely connected or independent tribal societies belonging to a diverse ethnolinguistic complex. As Chinese imperial power expanded southward, Chinese sources generalized the tribes of northern Vietnam at the time as Yue, or the Luoyue and the Ouyue (Lạc Việt and Au Viet). Over time, the term Yue morphed into a geopolitical designation rather than a term for a group of people, and it became more of a historical and political term than one tied to connotations of barbarism. During the period of Chinese rule, many states and rebellions in the former region of Yue (southern China and northern Vietnam) used the name Yue as an old geopolitical name rather than as an ethnonym.

When the word Yue (Middle Chinese: ɦʉɐt̚) was borrowed into the Vietnamese language during the late Tang dynasty (618–907) by the Austroasiatic Viet-Muong-speaking peoples, who were the ancestors of the modern-day Vietnamese Kinh, the exonym was gradually localized and became an endonym of the Vietnamese. That endonym might have manifested in different forms depending on how neighboring peoples interacted with and referred to the Vietnamese back then. For instance, until the modern day, the Cham have been calling the Vietnamese Yuen (Yvan), from the reign of Harivarman IV (1074–1080) to the present. It is evident that Vietnamese elites tried to tie their ethnic identity to the ancient Yue through constructed traditions during the late medieval period. However, all endonyms and exonyms referring to the Vietnamese, such as Viet, Kinh, or Kra-Dai Keeu, are related to political structures or have common origins in ancient Chinese geographical imagination. Most of the time, the Austroasiatic-speaking ancestors of the modern Kinh under one single ruler might have assumed for themselves a similar or identical designation, inherent in the modern Vietnamese first-person pronoun ta ("us, we, I"), to differentiate themselves from other groups. In the older colloquial usage, ta corresponded to "ours" as opposed to "theirs", and during colonial times, they were nước ta ("our country") and tiếng ta ("our language"), in contrast to nước tây ("western countries") and tiếng tây ("western languages").

Đại Cồ Việt was the name chosen by Đinh Bộ Lĩnh for his realm when he declared himself emperor in 966. It is probably derived from the vernacular Cự Việt ("Great Việt") or Kẻ Việt ("Việt Region"), with the Sino-Vietnamese Đại ("great") added as a prefix. The name appeared in the 15th-century text Đại Việt sử ký toàn thư but not the earlier 13th- or 14th-century text Đại Việt sử lược. According to Momoki Shiro, Đại Cồ Việt may have been the result of a mistake in the records or invented while compiling old records.

When Lý Nhật Tôn ascended to the throne in 1054, he dropped the vernacular nôm term Cồ from Đại Cồ Việt and shortened it to Đại Việt. The term Đại Việt Quốc ("the Great Viet State") has been found on brick inscriptions from Hoa Lư, the first capital of the polity, dating to the 10th century AD. The name Đại Việt is the more literary version of the name and had been in use since before its formalization in 1054.

For a thousand years, the area of what is now Northern Vietnam was ruled by a succession of Chinese dynasties as Nanyue, Giao Chỉ (交趾, Jiaozhi), Giao Châu (交州, Jiaozhou), Annan, and Jinghai Circuit.

Ancient northern Vietnam and particularly the Red River Delta were inhabited by various ethnolinguistic groups that constituted modern-day Hmong–Mien, Tibeto–Burman, Kra–Dai, and Austroasiatic-speaking peoples. Early societies had emerged and existed there for a while before the Han conquest in 111 BC, such as the Phùng Nguyên and Dong Son cultures. Both practiced metallurgy and sophisticated bronze-casting techniques. They were together called the Yue and barbarians by the Chinese and collectively understood as non-Chinese. Ancient Chinese texts do not give any distinction to each tribe and do not precisely indicate which languages or tribes they interacted with in northern Vietnam. All peoples living under the administration of the empire were usually referred to as either "people" (ren 人) or "subjects" (min 民). There was absolutely no classification or distinction for "Vietnamese", and it is difficult to identify people accurately as such or to infer modern ethnicity from the ancient. It is highly likely that these intermingled multilinguistic communities might have evolved into the present day without modern ethnic consciousness—until ethnic classification efforts carried out by the colonial government and successive governments of the Republic of Vietnam, Democratic Republic of Vietnam, and Socialist Republic of Vietnam—while retaining their intangible ethnic identity. There was no persistent "ethnic Vietnamese" identity during this period.

Official Vietnamese history textbooks usually assume that the people of northern Vietnam during Chinese rule were Việt/Yue. The Yue were broad groups of non-Chinese peoples of the south, which included many different ethnolinguistic groups who shared certain customs. After the disappearance of the Baiyue and the Lac Viet from Chinese records around the first century AD, new indigenous tribal groups might have emerged in the region under the name Li-Lao. The Li-Lao people were also known for their drum casting tradition. The culture produced Heger Type II drums, while the previous Dong Son culture of the Lac Viet produced Heger Type I drums.

The Li-Lao culture flourished from approximately 200 to 750 AD in present-day southern China and northern Vietnam. These Li tribes were recorded in Chinese sources as Lǐ (俚; "bandits") inhabiting the coastal areas between the Pearl River and Red River. Li political structures were distributed in numerous autonomous settlements/chiefdoms (dong 洞) located in riverine valleys. The Book of Sui notes that Li noblemen who possess a bronze drum in each dong were called dulao (都老), which Churchman argues bears some resemblance and cultural connection to the previous local ruling class of the Red River Delta. The Li tribes were described as ferocious raiding bandits who refused to accept imperial authority, leading to Jiaozhou, the heartland of the Red River Delta, being deemed by the Chinese to be an isolated borderland with difficult and limited administration. Because the Li-Lao people managed to keep themselves away from the Chinese sphere of cultural influence, the landscape of northern Vietnam during Han–Tang period experienced a degree of equilibrium between Sinification and localization. From the sixth to the seventh century, Chinese dynasties attempted to militarily subdue the Li dong, gradually causing the Li-Lao culture to decline.

In terms of complex culture and linguistics, the important effects of ten centuries of Chinese rule over northern Vietnam are arguably still observable. Some native languages of the regions for a long time had employed a Sinitic script and Sinitic-derived writing systems to represent their languages, such as Vietnamese, Tày, and Nùng.

James Chamberlain believes that the traditional Vietic realm was north central Vietnam and northern Laos, not the Red River Delta. Based on his interpretation of Keith Weller Taylor's examination of Chinese texts (Jiu Tangshu, Xin Tangshu, Suishu, Taiping Huanyu Ji, Tongdian), Chamberlain suggests that Việt-Mường peoples began emigrating from central Vietnam (Jiuzhen, Rinan) to the Red River Delta in the seventh century, during the Tang dynasty, possibly due to pressure from the Khmers in the south or the Chinese in the north. Chamberlain speculates that during the rebellion led by Mai Thúc Loan, the son of a salt-producing family in Hoan province (today Hà Tĩnh Province, North-Central Vietnam), which lasted from 722 to 723, a large number of Sinicized lowland Vietic people or the Kinh moved north. The Jiu Tangshu records that Mai Thúc Loan, also known as Mai Huyền Thành, styled himself as "the Black Emperor" (possibly after his swarthy complexion), and that he had 400,000 followers from 23 provinces across Annam and other kingdoms, including Champa and Chenla.

However, archaeogenetics demonstrate that before the Đông Sơn period, the Red River Delta's inhabitants were predominantly Austroasiatic: genetic data from Phùng Nguyên culture's Mán Bạc burial site (dated 1800 BC) have close proximity to modern Austroasiatic speakers; meanwhile, "mixed genetics" from Đông Sơn culture's Núi Nấp site show affinity to "Dai from China, Tai-Kadai speakers from Thailand, and Austroasiatic speakers from Vietnam, including the Kinh"; therefore, "[t]he likely spread of Vietic was southward from the RRD, not northward. Accounting for southern diversity will require alternative explanations." Churchman states that "the absence of records of large-scale population shifts indicates that there was a fairly stable group of people in Jiaozhi throughout the Han–Tang period who spoke Austroasiatic languages ancestral to modern Vietnamese". On a Buddhist inscription dated to the 8th century from Thanh Mai village, Hanoi, 100 out of 136 women mentioned in the epigraphy could be identified as ethnic Vietnamese females. Linguist John Phan proposes that a local dialect of Middle Chinese, called Annamese Middle Chinese, developed and was spoken in the Red River Delta by descendants of Chinese immigrants, and later was absorbed into the co-existing Việt-Mường languages by the ninth century. Phan identifies three layers of Chinese loanwords into Vietnamese: the earliest layer dates to the Han dynasty (ca. 1st century CE) and Jin dynasty (ca. 4th century CE); the late layer dates to the post-Tang period; and the recent layer dates to the Ming and Qing dynasties.

Study of northern Vietnam and the Red River Delta during the first millennium AD is problematic. This region is widely associated with the foundation of the modern country and nation-state of Vietnam. It has been given exceptional treatment and academic scrutiny compared to other regions. This unique academic focus has resulted in critical misinterpretations. Some notable academic works have echoed the established frameworks of colonial and postcolonial Vietnamese nationalist historiography in order to associate the entire history of the early Red River Delta with the Vietnamese, i.e., the Kinh, and the modern country of Vietnam. The rewriting of Vietnamese history in the 20th century considered pushing several nationalistic-themed theories. One notable theory, the "continuity", is defined as a belief that the peoples of the Red River Delta during the Han–Tang period had always retained their unique "Vietnamese identity" and "Vietnamese spirit", which was arguably rooted in the highly sophisticated Van Lang kingdoms under the Hung kings, which were largely legends transformed into "historical facts" under the scholarship of the Democratic Republic of Vietnam. This was despite relentless Chinese acculturation, making them "different" from other groups in southern China who "eventually lost their separate identities through assimilation into Chinese culture". The continuity theory reconstructed the emergence of the Đại Việt kingdom in the 10th century as the awakening and resurrection of "Vietnamese sovereignty", and these traditions of Vietnamese exceptionalism continued into modern Vietnam. For example, Keith Taylor took up some aspects of Vietnamese nationalist historiography in his 1983 monograph, The Birth of Vietnam, and falsely asserted that "Vietnam's independence resulted from a thousand-year struggle to throw off Chinese rule by a group of people who held a conviction 'that they were not and did not want to become Chinese.'" Later, Taylor retreated from Vietnamese nationalist historiography.

No evidence of "ethnic Vietnamese" resembling what would be considered the modern Vietnamese exists during the Han–Tang period. Instead, ancient northern Vietnam was very diverse and complex in terms of ethnolinguistic and cultural origins (as it still is today). The continuity theory can be easily discredited by linguistic examinations. By the 9th–11th centuries, the northern portion of the Viet-Muong portion of Vietic speakers had supposedly diverged, and one dialect cluster thereby evolved into Vietnamese. Other theories advocated by John Phan present evidence of the Vietnamese language being developed from a creolized language that resulted from a local linguistic shift from Middle Chinese to proto-Vietnamese after Sinitic rule.

Beside anachronisms, Vietnamese nationalist scholarship also inserted a "Vietnamese resistance" myth into history by labeling any rebellious local group in northern Vietnam during the Han–Tang period as collectively "Vietnamese" who 'were in constant struggles against the Chinese yokes', in contrast to "corrupt invading Chinese colonizers", generic modern nationalities and ethnicities. The context was heavily entangled with modern perceptions about Vietnam during decolonization and the Cold War. Historians such as Catherine Churchman have criticized attempts to characterize the past through the lens of modern national boundaries and project a "wish for the restoration of long-lost national independence" onto localized dynasties.

Prior to independence in the late 9th century, the area that became Đại Việt in northern Vietnam was ruled by the Tang dynasty as Annan. The hill dwellers on the western frontier of Annan and powerful chieftains such as Lý Do Độc allied with the state of Nanzhao in Yunnan and rebelled against the Tang dynasty in the 860s. They captured Annan in three years, forcing the lowlanders to scatter to throughout the delta. The Tang dynasty turned back and defeated the Nanzhao–indigenous alliance in 866 and renamed the area Jinghai Circuit. A military mutiny forced Tang authorities to withdraw in 880, while loyalist troops left for home on their own initiative.

A regional regime led by the Khúc family formed on the Red River Delta in the early 10th century. From 907 to 917, Khúc Hạo and then Khúc Thừa Mỹ were appointed by Chinese dynasties as jiedushi (tributary governors). The Khúc did not try to create any kind of a de jure independent polity. In 930, the neighboring Southern Han state invaded Annam and removed the Khúc from power. In 931, Dương Đình Nghệ, a local chief from Aizhou, revolted and quickly ousted the Southern Han. In 937, he was assassinated by Kiều Công Tiễn, leader of the revanchist faction allied with the Southern Han. In 938, emperor Liu Gong of the Southern Han led an invasion fleet to Annam to assist Kiều Công Tiễn. Dương Đình Nghệ's son-in-law Ngô Quyền, also from the south, marched north and killed Kiều Công Tiễn. He then led the people to fight and destroyed the Southern Han fleet on the Bạch Đằng River.

After defeating the Southern Han invasion, Ngô Quyền proclaimed himself king over the principality in 939 and established a new dynasty centered in the old Âu Việt's fortress of Cổ Loa. Cổ Loa's sphere of influence probably did not reach the other local nobility. In 944, after his death, Ngô Quyền's brother-in-law Dương Tam Kha (son of Dương Đình Nghệ) took power. The Dương clan increased factional segregation by bringing more southern men into the court. As a result, the principality broke apart during the reign of Tam Kha. Ngô Quyền's sons Ngô Xương Văn and Ngô Xương Ngập deposed their maternal uncle and became dual kings in 950. In 954, Ngô Xương Ngập died. The younger Ngô Xương Văn ruled as the sole king and was killed by warlords nine years later, which led to chaos across the Red River Delta.

The death of King Ngô Quyền brought a period of chaos and civil war from 965 to 968, and the country was divided between a dozen rebellious warlords with their own factions. A new leader emerged, named Đinh Bộ Lĩnh, from Hoa Lư. He and his son Đinh Liễn spent two years in political and military struggle. In 968, after defeating all twelve warlords, he unified the country. On his ascension, he renamed the country Đại Cồ Việt ("The Great Gau(tama)'s Việt") and moved his court to Hoa Lư. He became king of Đại Cồ Việt (r. 968–979) and titled himself emperor, while Đinh Liễn became the great prince. In 973 and 975, Đinh Bộ Lĩnh sent two embassies to the Song dynasty and established relationships. Buddhist clergy were put in charge of important positions. Coins were minted. The territories of the early Việt state comprised the lowland Red River basin to the Nghệ An region. According to a Hoa Lư inscription from c. 979, that year, Đinh Liễn murdered his brother Đinh Hạng Lang, who had been promoted to crown prince by his father. In late 979, both Đinh Bộ Lĩnh and Đinh Liễn were assassinated. Hearing the news, Ngô Nhật Khánh—a prince of the old royal family in exile—and king Paramesvaravarman I of Champa launched a naval attack on Hoa Lư, but much of the fleet was capsized by a late-season typhoon.

Queen Dương Vân Nga appointed her partner, general Lê Hoàn, chief of the state. Lê Hoàn's rivals then attacked him but were defeated. The queen of the Dương family decided to replace the Đinh with the Lê family of Lê Hoàn and brought the crown from her six-year-old son Đinh Toàn (r. 979–980) to Lê Hoàn (r. 980–1005) in 980. Disturbances in Đại Cồ Việt attracted attention from the Song dynasty. In 981, the Song emperor launched an invasion but was repulsed by Lê Hoàn. In 982, he attacked Champa, killed the Cham king Paramesvaravarman I, and destroyed a Cham city. A Khmer inscription (c. 987) mentioned that in that year, some Vietnamese merchants or envoys arrived in Cambodia through the Mekong.

After Lê Hoàn died in 1005, civil war broke out between crown princes Lê Long Việt, Lê Long Đĩnh, Lê Long Tích, and Lê Long Kính. Long Việt (r. 1005) was murdered by Long Đĩnh after ruling for only three days. As the Lê brothers fought each other, the Lý family—a member of the court's cadet, led by Lý Công Uẩn—quickly rose to power. Long Đĩnh (r. 1005–1009) ruled as a tyrant king and developed hemorrhoids, dying in November 1009. Lý Công Uẩn ascended the throne two days later, with support from the monkhood, as Lý Thái Tổ.

Emperor Lý Thái Tổ (r. 1009–1028) moved his court to the abandoned city of Đại La, which had previously been a seat of power under the Tang dynasty, and renamed it to Thăng Long in 1010. The city became what is now Hanoi. To control and maintain the nation's wealth, in 1013, Lý created a taxation system. His reign was relatively peaceful, though he campaigned against the Han communities in Hà Giang massif and subdued them in 1014. He furthermore laid the basis of a stable Vietnamese state, and his dynasty would rule the kingdom for the next 200 years.

Lý's son Lý Thái Tông (r. 1028–1053) and grandson Lý Thánh Tông (r. 1054–1071) continued to strengthen the Việt state. Starting during the reign of Lê Hoàn, the Việt expansion extended territories from the Red River Delta in all directions. The Vietnamese destroyed the Cham northern capital of Inprapura in 982; raided and plundered southern Chinese port cities in 995, 1028, 1036, 1059, and 1060; subdued the Nùng people in 1039; raided Laos in 1045; invaded Champa and pillaged Cham cities in 1044 and 1069; and subjugated the three northern Cham provinces of Địa Lý, Ma Linh, and Bố Chính. Contact between the Song dynasty of China and the Việt state increased through raids and tributary missions, which resulted in Chinese cultural influences on Vietnamese culture: the first civil examination based on the Chinese model was staged in 1075, the Chinese script was declared official at the court in 1174, and the emergence of the Vietnamese demotic script (Chữ Nôm) occurred in the 12th century.

In 1054, Lý Thánh Tông changed his kingdom's name to Đại Việt and declared himself emperor. He married an ordinary girl named Lady Ỷ Lan, and she gave birth to the crown prince Lý Càn Đức. In 1072, the infant became emperor Lý Nhân Tông (r. 1072–1127), the longest-ruling monarch in Vietnamese history. During the early years of Lý Nhân Tông, his father's military leader Lý Thường Kiệt, uncle Lý Đạo Thành, and Queen Ỷ Lan became court regents. From the 1070s, border tensions between the Song Empire, local Tai principalities, and the Việt kingdom broke out into open violence. In late 1075, Lý Thường Kiệt led a naval invasion of southern China. Việt troops wreaked havoc on Chinese border towns, then laid siege to Nanning and captured it one month later. The Song emperor sent a large counter-invasion of Đại Việt in late 1076, but Lý Thường Kiệt was able to fend it off and defeat the Chinese at the Battle of the Cầu River, where half of the Song forces died from combat and disease. Lý Nhân Tông then offered peace with the Song, and all hostilities ended in 1084; the Song subsequently recognized the Việt polity as a sovereign kingdom. According to a 14th-century chronicle, the Đại Việt sử lược, the Khmer Empire sent three embassies to Đại Việt in 1086, 1088, and 1095. The matured Lý Nhân Tông came to rule in 1085. He defeated the Cham ruler Jaya Indravarman II in 1103, built the Dạm Pagoda in Bắc Ninh in 1086, and constructed a Buddhist temple for his mother called Long Đọi pagoda in 1121. He died in 1127. One of his nephews, Lý Dương Hoán, succeeded him and became known as emperor Lý Thần Tông (r. 1128–1138). This marked the downfall of Lý family authority within the court.

Lý Thần Tông was crowned under the supervision of Lê Bá Ngọc, a powerful eunuch. Lê Bá Ngọc adopted a son of the emperor's mother, named Đỗ Anh Vũ. During the reign of Lý Thần Tông, Suryavarman II of the Khmer Empire launched an attack on Đại Việt's southern territories in 1128. In 1132, he allied with the Cham king Jaya Indravarman III and briefly seized Nghệ An and pillaged Thanh Hoá. In 1135, Duke Đỗ Anh Vũ raised an army and repelled the Khmer invaders. After the Chams refused to support them in 1137, Suryavarman II abandoned his incursions on Đại Việt and launched an invasion of Champa. At the same time, Lý Thần Tông began suffering from a fatal illness, and he died the next year, leaving the infant Lý Thiên Tộ to became emperor Lý Anh Tông (r. 1138–1175) under Đỗ Anh Vũ's patronage. After Đõ Anh Vũ died in 1159, another powerful figure, named Tô Hiến Thành, stepped into the role of guarding the dynasty, until 1179. In 1149, Javanese and Siamese ships arrived in Vân Đồn to trade. The sixth son of Lý Anh Tông, prince Lý Long Trát, was crowned in 1175 as Lý Cao Tông (r. 1175–1210).

By the 1190s, more outsider clans were able to penetrate and infiltrate the royal family, further weakening Lý authority. Three powerful aristocratic families—Đoàn, Nguyễn, and Trần (descendants of Trần emperors, a Chinese emigre from Fujian)—emerged at the court and contested it on behalf of the royals. In 1210, Lý Cao Tông's eldest son, Lý Sảm, became emperor Lý Huệ Tông of Đại Việt (r. 1210–1224). In 1224, Lý Sảm appointed his second princess, Lý Phật Kim, (empress Lý Chiêu Hoàng) as his successor while he abdicated and became a monk. Finally, in 1225, the Trần leader Trần Thủ Độ sponsored a marriage between his eight-year-old nephew Trần Cảnh and Lý Chiêu Hoàng, meaning the Lý would give up power to the Trần, and Trần Cảnh became emperor Trần Thái Tông of the new dynasty of Đại Việt.

During his reign, the young Trần Thái Tông centralized the monarchy, organized the civil examination on the Chinese model, built the Royal Academy and Confucian Temple, and ordered the construction and repair of delta dikes. In 1257, the Mongol Empire under Möngke Khan, who was waging a war to conquer the Song Empire, sent envoys to Trần Thái Tông and demanded the emperor of Đại Việt to present himself to the Mongol khan in Peking. When the demand was rejected and the envoys were imprisoned, about 25,000 Mongol–Dali troops, led by general Uriyangqadaï, invaded Đại Việt from Yunnan and then attacked the Song Empire from Đại Việt. Unprepared, Trần Thái Tông's army was overwhelmed at the battle of Bình Lệ Nguyên on 17 January 1258. Five days later, the Mongols captured and sacked Thăng Long. The Mongols retreated to Yunnan fourteen days later, as Trần Thái Tông had submitted and sent tribute to Möngke.

Trần Thái Tông's successors Trần Thánh Tông (r. 1258–1278) and Trần Nhân Tông (r. 1278–1293) continued to send tribute to the new Mongol-led Yuan dynasty. In 1283, Yuan emperor Kublai Khan launched an invasion of Champa. In early 1285, he commissioned prince Toghon to lead the second invasion of Đại Việt to punish the Vietnamese emperor Trần Nhân Tông for not helping the Yuan campaign in Champa and refusing to send tribute. Kublai also appointed Trần Ích Tắc, a Trần prince, as the puppet emperor of Đại Việt. Though Yuan forces initially captured Thăng Long, they were ultimately defeated by the Cham–Vietnamese alliance in June. In 1288, they decided to launch the third and largest invasion of Đại Việt but were repelled. Prince Trần Hưng Đạo ended the Mongol yoke through a decisive naval victory in the battle of Bạch Đằng River in April 1288. Đại Việt continued to flourish under the reigns of Trẩn Nhân Tông and Trần Anh Tông (r. 1293–1314).

By the 14th century, the Đại Việt kingdom began experiencing a long decline. The population is estimated to have grown from 1.2 million in 1200 to perhaps 2.4 million in 1340. The transitional decade (1326–36) from the end of the Medieval Warm Period to the Little Ice Age severely affected the climate of the Red River Delta. Weather phenomena such as drought, violent flooding, and storms frequently occurred, which weakened irrigation systems, damaged agricultural production, generated famines, and impoverished the peasantry, which together with widespread non-bubonic plagues unleashed robbery and chaos.

Trần Anh Tông seized northern Champa in 1307, intervening in its politics through the marriage of Cham king Jaya Simhavarman III with Trần Anh Tông's sister, queen Paramecvariin. Trần Minh Tông (r. 1314–1329) entered conflict with the Tai people in Laos and Sukhothai from the 1320s to the 1330s. During the reign of the weak king Trần Dụ Tông (r. 1341–1369), internal rebellions led by serfs and peasants from the 1340s and 1360s weakened royal power. In 1369, due to Trần Dụ Tông's lack of an heir, power was seized by Dương Nhật Lễ, a man from the Dương clan. A short bloody civil war led by the royal Tran family against the Dương clan broke out in 1369–1370, creating turmoil. The Trần enthroned Trần Nghệ Tông (r. 1370–1372), while Dương Nhật Lễ was deposed and executed.

Dương's queen mother went into exile in Champa and begged the Cham king Po Binasuor (Chế Bồng Nga) to help her get revenge. In response, the Champa empire under Po Binasuor invaded Đại Việt and ransacked Thăng Long in 1371. Six years later, the Đại Việt army suffered a great defeat at Battle of Vijaya, and Trần Duệ Tông (r. 1373–1377) was killed. The Chams then continued to advance north, besieging, pillaging, and looting Thăng Long four times from 1378 to 1383. War with Champa ended in 1390 after Po Binasuor was killed during his northward offensive by Vietnamese forces led by prince Trần Khát Chân, who used firearms in battle.

Hồ Quý Ly (1336–1407), the minister of the Trần court who had desperately fought off the Cham invasions, now became the most powerful figure in the kingdom. He conducted a series of reforms, including replacing copper coins with banknotes, despite the kingdom still recovering from the devastating war. Over time, he slowly eliminated the Trần dynasty and aristocracy. In 1400, he deposed the last Trần emperor and became ruler of Đại Việt. Hồ Quý Ly became emperor, moved the capital to Tây Đô, and briefly changed the kingdom's name to Đại Ngu ("great joy/peace") (大虞). In 1401, he stepped down and established as king his second son, Hồ Hán Thương (r. 1401–1407), who had Trần ancestry.

In 1406, emperor Yongle of the Ming dynasty, in the name of restoring the Trần dynasty, invaded Đại Ngu. The ill-prepared Vietnamese resistance of Hồ Quý Ly, who failed to get support from his people, especially from the Thăng Long literati, was defeated by a Chinese army of 215,000, armed with the newest technology at the time. Đại Ngu became the thirteenth province of the Ming empire. A line of the Trần dynasty, the Later Trần, continued to rule the southern part of Đại Việt and led Vietnamese rebellions against the Ming empire, until being subdued in 1413.

The short-lived Ming colonial rule had traumatic impacts on the kingdom and the Vietnamese. In pursuit of their sinicization, the Ming opened Confucian schools and shrines, prohibited old Vietnamese traditions such as tattooing, and sent several thousand Vietnamese scholars to China, where they were re-educated in Neo-Confucian classics. Some of these literati would dramatically change the Vietnamese state under the new Lê dynasty when they returned in the 1430s and served the new court, triggering a major shift from Mahayana Buddhism to Confucianism. The remnants of pre-1400s Buddhist sanctuaries and temples in Hanoi were systematically demolished and removed.

Lê Lợi, the son of a peasant from the Thanh Hoá region, led an uprising against the Chinese occupation starting in February 1418. He led a war of independence against Ming colonial rule that lasted for 9 years. Assisted by Nguyễn Trãi, a prominent anti-Ming scholar, and other Thanh Hoá families—the Trịnh and the Nguyễn—his rebel forces managed to capture and defeat several major Ming strongholds and counterattacks, and eventually drove the Chinese back to the north in 1427. In April 1428, Lê Lợi was proclaimed Emperor of a new Đại Việt. He established Hanoi as Đông Kinh or the eastern capital, while the dynasty's estate Lam Son became Tây Kinh or the western capital.

Through his proclamation, Lê Lợi called upon educated men of ability to come forward to serve the new monarchy. The old Buddhist aristocrats were stripped during the Ming occupation and gave rise to the new emerging literati class. For the first time, a centralized authority based on proper laws was instituted. Literary examination now became crucial for the Việt state, and scholars like Nguyễn Trãi played a large role in the court.

Lê Lợi shifted his main affair focus to the Tai people and the Laotian Lan Xang kingdom in the west, due to their betrayal and subsequent alliance with the Ming during his rebellion in the 1420s. In 1431 and 1433, the Việt launched several campaigns on various Tai polities, subdued them, and incorporated the northwest region into Đại Việt.