Gustav Sicher (August 31, 1880 in Klatovy – October 5, 1960) was a chief rabbi of Prague. Sicher was a student at the Vienna Rabbinical Seminary and also studied philosophy at Charles University under Tomáš Garrigue Masaryk. He first held rabbinical office in 1905 in Náchod, and took part in Zionist organizations, participating in Mizrachi and founding an organization called the Sinai Association. During World War I, he served as a Feldrabbiner (chaplain) in the Austrian army. In 1921, he ran for office as a candidate of the Jewish Party (Židovská strana). He served as rabbi of the synagogue o