Mitrofan Viktorovich Dovnar-Zapol'skiy (Belarusian: Мітрафан Віктаравіч Доўнар-Запольскі, Russian: Митрофан Викторович Довнар-Запольский; 14 June [O.S. 2 June] 1867, Rechytsa, Minsk Governorate — 30 September 1934, Moscow) was a historian, ethnographer, and diplomat of Belarusian origin. He hailed from the family of land-less smaller nobility and was the son of Collegiate Secretary.
He was the author of more than 150 works on the history of Kievan Rus', Muscovy, 19th-century Russia, Lithuania and Belarus, on the social-political movement, peasants' question and the ethnography of Belarus. Notably, the majority of his works were of a scientific-analytical nature. He extensively sourced his works on the materials from more than 20 archives in Moscow, Saint Petersburg, Kiev, Vilna, Warsaw, Cracow, Lviv, Kostroma, Yaroslavl', Novgorod, Nyasvizh etc. Many of his works remain unpublished. He was awarded the Order of Saint Vladimir 4th grade (April 1916) for his scientific work.
An alumnus of the historical-philological faculty of Kiev University (1893), he wrote a magister dissertation on history in Fall 1901 and a doctoral dissertation on history in 1906. He became Professor at Moscow University (1899) and professor of Russian history at Kiev University in 1902. He was the organiser and director of the Higher Commercial Courses (Kiev, 1906), one of the organizers and the first head of the South-Western Branch of the Russian Exports Chamber (1912), and head of several popular-scientific circles and societies in Kiev.