Boris Yefimovich Shtein (Russian: Бори́с Ефи́мович Штейн; 1892 – 14 March 1961)[1] was a Soviet diplomat and historian. He was a member of many Soviet delegations in the 1920s and 1930s and served as a diplomat at the United Nations in the 1940s. In later life Shtein dedicated himself to academic work as a professor and writer on the history of Soviet foreign relations. His name is also transliterated as Boris Stein or Boris Shteyn.