Johannes Clauberg (born 24th February 1622 in Solingen/Germany - died 31st January 1665 in Duisburg) was a German theologian and philosopher. Clauberg was the founding Rector of the first Duisburg University , where he taught from 1655 to 1665. He was much influenced by the rationalism of Descartes.

After travelling in France and England, he studied the Cartesian philosophy under John Raey at Leiden. In 1649, he became professor of philosophy and theology at Herborn, but subsequently (1651), in consequence of the jealousy of his colleagues, accepted an invitation to a similar post at Duisburg.

Clauberg was one of the earliest teachers of the new doctrines in Germany and an exact and methodical commentator on his masters writings. His theory of the connection between the soul and the body is in some respects analogous to that of Malebranche; but he is not therefore to be regarded as a true forerunner of Occasionalism, as he uses Occasion for the stimulus which directly produces a mental phenomenon, without postulating the intervention of God (H. Müller, J. Clauberg und seine Stellung im Cartesianismus). His view of the relation of God to his creatures is held to foreshadow the pantheism of Spinoza. All creatures exist only through the continuous creative energy of the Divine Being, and are no more independent of his will than are our thoughts independent of us, or rather less, for there are thoughts which force themselves upon us whether we will or not.

For metaphysics Clauberg suggested the names ontosophy or ontology, the latter being afterwards adopted by Wolff. He also devoted considerable attention to the German languages, and his researches in this direction attracted the favorable notice of Leibnitz.

His chief works are: De conjunctione animae et corporis humani; Exercitationes centum de cognitione Dei et nostri; Logica vetus et nova; Initiatio philosophi, seu Dubitalio Cartesiana, a commentary on Descartes Meditations; and Ars etymologica Teutonum.

A collected edition of his philosophical works was published at Amsterdam (1691), with life by H. C. Hennin; see also E. Zeller, Geschichte der deutschen Philosophie seit Leibnitz (1873).