Willy Cohn (12 December 1888 in Breslau – 29 November 1941 in Kaunas, Lithuania) was a German historian and teacher.
During the Nazi era, he documented the Jewish life in Breslau in his diaries, until he and his family were deported to German-occupied Lithuania and killed.
Cohn's diaries, translated into English and condensed, were published in 2012 as No Justice in Germany: The Breslau Diaries, 1933-1941 by Stanford University Press.
Along with Victor Klemperer, Cohn was one of the most important chroniclers of the crimes of the Nazi regime against the Jewish people.