The Roman Catholic Diocese of Frederico Westphalen () is a diocese located in the city of Frederico Westphalen in the ecclesiastical province of Passo Fundo in Brazil.
History 22 May 1961: Established as Diocese of Frederico Westphalen from the Diocese of Passo Fundo and Diocese of Santa Maria
Leadership Bishops of Frederico Westphalen (Roman rite) João Aloysio Hoffmann † (26 March 1962 - 27 May 1971) Appointed, Bishop of Erexim Bruno Maldaner † (27 May 1971 - 12 December 2001) Retired Zeno Hastenteufel (12 December 2001 - 28 March 2007) Appointed, Bishop of Novo Hamburgo Antônio Carlos Rossi Keller (11 June 2008 – present)
References GCatholic.org Catholic Hierarchy Diocese website (Portuguese)