Stephan Alexander Würdtwein (1719 – 11 April 1796) was a German theologian, auxiliary bishop of Worms, and historian, particularly of the Catholic Church and of the history of the city of Mainz.
He studied philosophy, theology, and canon law at the University of Heidelberg from 1738 to 1743, while living in the seminary.
Next he studied canon law and dogma at the Catholic seminary in Mainz, and was ordained a priest on 18 July 1745.
On the basis of his extensive study of canon law, he was honored in 1758 as geistlicher Rat and given a position on the Vicar general's council, the central power of the electorate.
Because the archives of the Electorate of Mainz were dispersed and partly destroyed, his publications are of great importance to Germania Sacra.