Friedrich Karl Otto Dibelius (15 May 1880 – 31 January 1967) was a German bishop of the Evangelical Church in Berlin-Brandenburg, up to 1934 a conservative anti-semite who became a staunch opponent of Nazism and communism.
He was born in Berlin, Brandenburg, in 1880. One of his cousins was the Protestant theologian Martin Dibelius. From 1899 to 1903 he studied at the Frederick William University of Berlin. He received his PhD in 1902. From 1904–1906, he studied at the Preachers' Seminary in Wittenberg.
He was then employed as a minister by the Evangelical State Church of Prussia's older Provinces. In 1906–1907, he was the assistant pastor at the Klosterkirche in Guben. In 1907–1909, he was the archdeacon at St. Mary's Church in Crossen an der Oder. In 1909–1910, he was the assistant pastor at the Church of Ss. Peter and Paul in Danzig. From 1911 to 1915, he was the chief pastor at Lauenburg in Pomerania. From 1915 to 1925, he was the pastor of the Heilsbronnen congregation in Berlin-Schöneberg. In 1918, he was the executive secretary (part-time) of the Mutual Trust Council in the Evangelical Supreme Ecclesiastical Council (German: Evangelischer Oberkirchenrat, EOK) of the Evangelical State Church in Prussia's older Provinces, which renamed after the separation of state and religion into Evangelical Church of the old-Prussian Union (APU) in 1922.