Johann Heinrich Christoph Willibald Beyschlag (5 September 1823 – 25 November 1900 in Halle an der Saale) was a German theologian from Frankfurt am Main.

He studied theology at the Universities of Bonn and Berlin, afterwards serving as an assistant pastor in Koblenz (1849), then as a pastor in Trier (1850). During the following year, Beyschlag began working as a religious instructor in Mainz. In 1856 he became a court preacher in Karlsruhe, and four years later, he was appointed a professor of practical theology and New Testament exegesis at the University of Halle.^[1]

Beyschlag was the leader of the Kirchenpartei^[2] called Mittelpartei ("Middle Party"), and in 1876, with Albrecht Wolters, founded the Deutsch-evangelische Blätter (a publication of the Mittelpartei in the Kirche der Altpreußischen Union). Because of the combative nature of the magazine, he was once sued for libel.^[1][3] Also, he was a primary catalyst in the founding of the Evangelischer Bund [de] (Protestant Confederation) —^[4] he believed that only in unity could German Protestantism find strength.

He was a leading supporter of the Vermittlungstheologie and was opposed to Chalcedonian Christology.^[4] Also, he stood for the rights of the laity, and believed in the autonomy of the church, leading him to be in favor of separation of church and state.^[5][6] Beyschlag was viewed as an antagonist of the Roman Catholic Church and a sharp critic of Ultramontanism.^[1]

In 1891 he published Neutestamentliche Theologie, oder, geschichtliche Darstellung der lehren Jesu und des Urchristenthums nach den neutestamentlichen Quellen, a book that was later translated into English and published as "New Testament theology; or, Historical account of the teaching of Jesus and of primitive Christianity according to the New Testament sources" (translation by Rev. Neil Buchanan; 1895). The following are a few of his many other writings:

• Die Christologie des Neuen Testaments : ein biblisch-theologischer Versuch, 1866 – Christology of the New Testament.
• Godofred, ein Märchen fürs deutsche Haus, 1890 – Godofred. A fairytale for German households.
• Das Leben Jesu, 1887 – The life of Jesus.
• Bischof D. Reinkens und der deutsche Altkatholizismus, 1896 – Bishop Joseph Hubert Reinkens and German Old Catholicism.
• Deutschland im Laufe des neunzehnten Jahrhunderts, 1900 – Germany during the nineteenth century.^[7]