Anti-Normanism is an opposition to Normanism, the mainstream narrative of the Viking Age in Eastern Europe, and concerns the origin theory of Kievan Rus' that emerged in the 18th and 19th centuries. At the centre of the disagreement is the origin of the Varangian Rus', a people who travelled across and settled in Eastern Europe in the 8th and 9th centuries, and are considered by most modern historians to be of Scandinavian origin, but soon assimilated with the Slavs. Since the Normanist theory has been firmly established as mainstream, modern Anti-Normanism is viewed historical revisionism.

Kievan Rus', also known as Kyivan Rus', was a state and later an amalgam of principalities in Eastern and Northern Europe from the late 9th to the mid-13th century. The name was coined by Russian historians in the 19th century. Encompassing a variety of polities and peoples, including East Slavic, Norse, and Finnic, it was ruled by the Rurik dynasty, founded by the Varangian prince Rurik. The modern nations of Belarus, Russia, and Ukraine all claim Kievan Rus' as their cultural ancestor, with Belarus and Russia deriving their names from it, and the name Kievan Rus' derived from what is now the capital of Ukraine. At its greatest extent in the mid-11th century, Kievan Rus' stretched from the White Sea in the north to the Black Sea in the south and from the headwaters of the Vistula in the west to the Taman Peninsula in the east, uniting the East Slavic tribes.