Theodor Granderath (19 June 1839, Giesenkirchen, Rhine Province – 19 March 1902, Valkenburg, Netherlands) was a German Jesuit scholar.
After completing the course in the gymnasium at Neuss, he studied theology in the University of Tübingen, and entered the Society of Jesus at Münster, Westphalia (3 April 1860).
This was followed by the Constitutiones dogmaticae s. oecumenici Concilii Vaticani ex ipsis ejus actis explicatae atque illustratae (Freiburg im Br., 1892).
Two volumes of this work, which the author himself prepared for the press, were issued in 1903 at Freiburg im Breisgau, the first dealing with the preliminary history and the second with the proceedings of the council to the end of the third public session.
Granderath was also the author of many apologetic, dogmatic, and historical articles in the Stimmen aus Maria-Laach (1874–99), the Zeitschrift für katholische Theologie (1881–86), and the Katholik (1898).