Valentin Fyodorovich Bulgakov (Russian: Валентин Фёдорович Булгаков; 25 November 1886 in Kuznetsk, Russian Empire – 22 September 1966 in Yasnaya Polyana, Tula Oblast, Soviet Union) was the last secretary of Leo Tolstoy and his biographer. He was director of a number of literary museums and was engaged in Tolstoyan, pacifist activities. He was imprisoned by the Tsarist regime and in a Nazi internment camp. During the final 20 years of his life he was head of the Yasnaya Polyana museum.