Leonid Borisovich Kogan (Russian: Леони́д Бори́сович Ко́ган; Ukrainian: Леонід Борисович Коган; 14 November 1924 – 17 December 1982) was a preeminent Soviet violinist during the 20th century. Many consider him to be among the greatest violinists of the 20th century. In particular, he is considered to have been one of the greatest representatives of the Soviet School of violin playing.