Russian imperialism refers to the political, economic, cultural, and military power or control exerted by Russia and its predecessor states, over other countries and territories. It includes the conquests of the Tsardom of Russia, the Russian Empire, the imperialism of the Soviet Union, and the neo-imperialism of the Russian Federation. Some postcolonial scholars have noted the lack of attention given to Russian and Soviet imperialism in the discipline.

After the Fall of Constantinople (1453), Moscow named itself the third Rome, following the Roman and Byzantine Empires. Beginning in the 1550s, Russia conquered, on average, territory the size of the Netherlands every year for 150 years. This included Siberia, Central Asia, the Caucasus and parts of Eastern Europe. Russia engaged in settler colonialism in these lands, and also founded colonies in North America, notably in present-day Alaska. At its height in the late 19th century, the Russian Empire covered about one-sixth of the world's landmass, making it the third-largest empire in history.

In the late 18th century, the emperors promoted the concept of an "All-Russian nation" made up of Great Russians, Little Russians (Ukrainians) and White Russians (Belarusians), to bolster Russian imperial claims to parts of the partitioned Polish–Lithuanian Commonwealth. Emperor Nicholas I made "Orthodoxy, Autocracy, and Nationality" the official imperial ideology, which sought to unite the empire's many peoples through Eastern Orthodox Christianity, loyalty to the emperor, and Russianness.

In the Russian Civil War, the Russian Bolsheviks seized control of the former empire's territories and founded the Soviet Union (USSR). Although claiming to be anti-imperialist, it had many similarities with empires. It was involved in many foreign military interventions and in regime change throughout the world, as well as Sovietization. Under Joseph Stalin, the USSR pursued internal colonialism in Central Asia by massive forced resettlement. Under the Molotov–Ribbentrop Pact, the Soviet Union and Nazi Germany divided eastern Europe between themselves. At the end of World War II, most eastern and central European countries were occupied by the USSR; these Eastern Bloc countries were widely regarded as Soviet satellite states.

Since the 2010s, analysts have described Russia under Vladimir Putin as neo-imperialist. Russia occupies parts of neighboring countries and has engaged in expansionism, most notably with the 2008 Russian invasion of Georgia, the 2014 annexation of Crimea, and the 2022 invasion of Ukraine and annexation of its southeast. Russia has also established domination over Belarus. The Putin regime has revived imperial ideas such as the "Russian world" and the ideology of Eurasianism. It has used disinformation and the Russian diaspora to undermine the sovereignty of other countries. Russia is also accused of neo-colonialism in Africa, mainly through the activities of the Wagner Group and Africa Corps.

Montesquieu wrote that "The Moscovites cannot leave the empire" and they "are all slaves". Historian Alexander Etkind describes a phenomenon of "reversed gradient", where people living near the center of the Russian Empire experienced greater oppression than the ones on the edges. Jean-Jacques Rousseau in turn argued that Poland was not free because of Russian imperialism. In 1836, Nikolai Gogol said that Saint Petersburg was "something similar to a European colony in America", remarking that there were as many foreigners as people of the native ethnicity. According to Aleksey Khomyakov, the Russian elite was "a colony of eclectic Europeans, thrown into a country of savages" with a "colonial relationship" between the two. A similar colonial aspect was identified by Konstantin Kavelin.

Russian imperialism has been argued to be different from other European colonial empires due to its empire being overland rather than overseas, which meant that rebellions could be more easily put down, with some lands being reconquered soon after they were lost. The terrestrial basis of the empire has also been seen as a factor which made it more divided than sea-based ones due to the difficulties of communication and transport over land at the time.

Russian imperialism has been linked to the labour-intensive and low productivity economic system based on serfdom and despotic rule, which required constant increase in the amount of land under cultivation to legitimise the rule and provide satisfaction to the subjects. The political system in turn depended on land as a resource to reward officeholders, and thus the political elite made territorial expansion an intentional project.^{[citation needed]}