Simon Dubnow (alternatively spelled Dubnov; Yiddish: שמעון דובנאָװ, romanized: Shimen Dubnov; Russian: Семён Ма́ркович Ду́бнов, romanized: Semyon Markovich Dubnov, IPA: [sʲɪˈmʲɵn ˈmarkəvʲɪdʑ ˈdubnəf]; 10 September 1860 – 8 December 1941) was a Jewish-Russian historian, writer and activist.