Ivan Ivanovich Meshchaninov (Russian: Иван Иванович Мещанинов; 6 December 1883 – 16 January 1967) was a Soviet linguist and ethnographer.
He became a member of the Academy of Sciences of the Soviet Union, as a historian, in 1932 and was director of the Peter the Great Museum of Anthropology and Ethnography from 1934 to 1937.
He advocated the idea of notional categories that is also found in Otto Jespersen's works, studied polysynthetic languages and syntax.
Then in 1948 a move against the Anti-Marrists was initiated, in which however it was not Meshchaninov himself who played a major role, but rather younger Marrists as Fedot Filin, depicting such people as Viktor Vinogradov and Aleksandr Reformatskii as "bourgeois idealists".
This term, derived from the tsarist military officer Aleksey Arakcheyev (1768–1834), means a regime having "... a policy of extreme reaction, police despotism and crude militarism".