9 April] 1882 – 9 September 1953) was a Russian and Soviet historian noted for his comprehensive studies of Kievan Rus and the Golden Horde.

Grekov was accused of participating in the White Movement in the Crimea during the civil war, and in 1930, his son was arrested in connection with the "Platonov Affair" and sent to the Solovki Islands Penal Colony.

Both of these facts were widely known in the 1930s, and this led Grekov to make wide-ranging concessions to the official ideology during the Stalin Purges and, according to A. H. Plakhonin, to write scholarship "on order" for the regime.

In this work, steeped in Marxist–Leninist ideology, he stressed the agricultural rather than commercial basis of the economy of this polity and argued that the heritage of Kievan Rus' was equally shared by modern Russia, Ukraine, and Belarus.

His student, Vladimir Pashuto, carried this work forward and began the collection of foreign sources for the medieval period in the history of the Eastern Slavs.