The Bagrationi dynasty (/bʌɡrʌtiˈɒni/; Georgian: ბაგრატიონი, romanized: bagrat'ioni [ˈbäɡɾätʼio̞n̪i]) is a royal dynasty which reigned in Georgia from the Middle Ages until the early 19th century, being among the oldest extant Christian ruling dynasties in the world. In modern usage, the name of the dynasty is sometimes Hellenized and referred to as the Georgian Bagratids, also known in English as the Bagrations. Originally comes from the Armenian Bagratuni dynasty.

The origins of the dynasty are disputed. Most scholars agree that the dynasty comes from the Armenian Bagratuni dynasty, and is seen as a smaller branch of the Bagratids. The early Georgian Bagratids gained the Principality of Iberia through dynastic marriage after succeeding the Chosroid dynasty at the end of the 8th century. In 888 Adarnase IV of Iberia restored the Georgian monarchy; various native polities then united into the Kingdom of Georgia, which prospered from the 11th to the 13th century. This period of time, particularly the reigns of David IV the Builder (1089–1125) and of his great-granddaughter Tamar the Great (1184–1213) inaugurated the Georgian Golden Age in the history of Georgia.

After fragmentation of the unified Kingdom of Georgia in the late 15th century, the branches of the Bagrationi dynasty ruled the three breakaway Georgian kingdoms, the Kingdom of Kartli, the Kingdom of Kakheti, and the Kingdom of Imereti, until Russian annexation in the early-19th century. While the 3rd article of the 1783 Treaty of Georgievsk guaranteed continued sovereignty for the Bagrationi dynasty and their continued presence on the Georgian throne, the Russian Empire later broke the terms of the treaty and fully annexed the protectorate. The dynasty persisted within the Russian Empire as an Imperial Russian noble family until the 1917 February Revolution. The establishment of Soviet rule in Georgia in 1921 forced some members of the family to accept demoted status and loss of property in Georgia. Other members relocated to Western Europe, but some Bagrations repatriated after Georgia regained independence in 1991.

The earliest Georgian forms of the dynastic name are Bagratoniani, Bagratuniani and Bagratovani, changed subsequently into Bagrationi. These names as well as the Armenian Bagratuni and the modern designation Bagratid mean "the children of Bagrat" or "the house of/established by Bagrat", Bagrat being a given name of Iranian origin. The origins of the Bagratid dynasty is still matter of debate between Georgian and Armenian scholars. Georgian scholars argue that the Bagrationis were of Georgian origin, while Armenian and Western scholars believe them to be a branch of the Armenian Bagratunis.

According to a tradition first recorded in the work of the 11th-century Georgian chronicler Sumbat Davitis-Dze and repeated much later by Prince Vakhushti Bagrationi (1696–1757), the dynasty claimed descent from the biblical king and prophet David and came from Israel around 530 AD. The tradition had it that of seven refugee brothers of the Davidic line, three of them settled in Armenia and the other four arrived in Kartli (also known as Iberia), where they intermarried with the local ruling houses and acquired some lands in hereditary possession, with one of the four brothers, Guaram (died in 532), founding a line subsequently called Bagrationi after his son Bagrat. A successor, Guaram, was installed as a presiding prince of Iberia under the Byzantine protectorate, receiving on this occasion the Byzantine court title of Kouropalates in 575. Thus, according to this version, began the dynasty of the Bagrationis, who ruled until 1801.

This tradition enjoyed a general acceptance until the early 20th century. The Jewish origin, let alone the biblical descent, of the Bagratids has been discounted by modern scholarship. Cyril Toumanoff's research concluded that the Georgian Bagratids branched out of the Armenian Bagratid dynasty in the person of Adarnase, whose father Vasak (son of Ashot III the Blind, presiding prince of Armenia from 732 to 748) passed to Kartli following an abortive uprising against Arab rule in 775. Adarnase’s son, Ashot I, acquired the Principality of Iberia in 813 and thus founded the last royal house of Georgia. Accordingly, the legend of the Davidic origin of the Georgian Bagratids was a further development of the earlier claim entertained by the Armenian dynasty, as given in the work of the Armenian author Moses of Khorene. Once the Georgian branch, which had quickly acculturated in the new environment, assumed royal power, the myth of their biblical origin helped to maintain their legitimacy and became a major ideological pillar of their millennium-long rule of Georgia.

The generation-by-generation history of the Bagrationi dynasty begins only in the late 8th century. Toumanoff claimed that the first Georgian branch of the Bagratids may be traced as far back as the 2nd century AD, when they were said to rule over the princedom of Odzrkhe in what is now southern Georgia. The Odzrkhe line, known in the medieval annals as the Bivritianis, lasted until the 5th century AD. They cannot, however, be considered the direct ancestors of the later Bagratids who eventually restored Georgian royal authority. Pavle Ingorokva suggested that the Bagrations were a branch of the Pharnavazid dynasty of the Kingdom of Iberia.

The Bagrationi family had grown in prominence by the time the Georgian monarchy (Caucasian Iberia) fell to the Sassanid Persian Empire in the 6th century, and the leading local princely families were exhausted by Arab attacks. The rise of the new dynasty was made possible by the extinction of the Guaramids and the near-extinction of the Chosroids, the two earlier dynasties of Iberia with whom the Bagratids extensively intermarried, and also by the Abbasid preoccupation with their own civil wars and conflict with the Byzantine Empire. Although Arab rule did not allow them a foothold in the ancient capital of Tbilisi and eastern Kartli, the Bagratids successfully maintained their initial domain in Klarjeti and Meskheti and, under the Byzantine protectorate, extended their possessions southward into the northwestern Armenian marches to form a large polity conventionally known in modern history as Tao-Klarjeti. In 813, the new dynasty acquired, with Ashot I, the hereditary title of presiding prince of Iberia (Kartli), to which the emperor attached the honorific of kourapalates.^{[citation needed]}