Jakob Merten (August 11, 1809 - February 22, 1872) was a German Catholic theologian who was born in Wittlich.
He studied theology in Trier, where in 1833 he received his ordination. Subsequently he became a chaplain in Trier, where he worked closely with Franz Peter Knoodt (1811-1889). From 1843 to 1868 he was a professor of philosophy at the Episcopal Seminary in Trier.
Initially a prominent follower of Anton Genther's philosophy, Merten eventually abandoned Gentherianism as his career progressed. He was author of an essay on Gentherian philosophy titled Hauptfragen der Metaphysik in Verbindung mit der Speculation (Primary Questions of Metaphysics in Association with Speculation) (1840). Other noted works by Merten include:
Grundriss der Metaphysik, (Outline of Metaphysics); 1848
Der selige Frings und sein Freund als Antigentherianer; 1852
Bemerkungen zur Metaphysik von Balmes, (Remarks on the Metaphysics of Balmes); 1859