Ivan Shamiakin was a Soviet Belarusian writer, perhaps one of the most prolific of the Soviet BSSR, writing in a socialist realist style.

Ivan Leontievich Leontiev was a Russian army officer who wrote plays and novels under the pen name Ivan Shcheglov. His best known work is The Dacha Husband (Dachnyi muzh). The first English translation of Shcheglov's novel was made by Michael R. Katz in 2009.

Ivan Shevtsov was a Soviet novelist, known in the West for the anti-semitic aspects of his 1965 novel Aphid.

Ivan Shishmanov was a Bulgarian writer, ethnographer, politician and diplomat. He served as Ambassador of Bulgaria to the Ukrainian State and the Ukrainian People's Republic.

Ivan Sergeyevich Shmelyov was a Russian writer best known for his full-blooded idyllic recreations of the pre-revolutionary past spent in the merchant district of Moscow. He was a member of the Moscow literary group Sreda. After the October Revolution Shmelyov fled to France, becoming an émigré writer.

Ivan Anatolievich Shpitsberg, was a Russian and Soviet lawyer, journalist, writer, translator, organizer, and head of the scientific society and publishing house Atheist (1921), and editor of the eponymous magazine.

Ivan Mikhailovich Snegiryov was one of the first Russian ethnographers. He published detailed descriptions of almost every church and monastery in Moscow.

Ivan Softa was a Croatian writer and poet. He was often compared to Maxim Gorky because his first novel Na cesti is known as one of the best Croatian social realism books.

Ivan Sergeevich Sokolov-Mikitov was a Russian/Soviet writer and journalist who took part in numerous journeys and expeditions. Sokolov-Mikitov, best known for his engaging traveller's sketches, was also regarded as a fine nature-observing stylist, in the line of Konstantin Paustovsky and Mikhail Prishvin. Following the tradition of Russian realism, but still influenced by 1900s modernist authors, Sokolov-Mikitov developed his individual style of writing, incorporating elements of traditional Russian folk tales, bylinas and fables. Autobiographical novel Childhood (1931) is regarded as one of his finest.

Ivan Hryhorovych Sokulskyi was a Ukrainian poet, Soviet dissident and human rights activist who was a member of the Ukrainian Helsinki Group.