Maria Thaddäus von Trautmannsdorff (28 May 1761 – 20 January 1819) was a cardinal of the Roman Catholic Church.

[1] He was born on 28 May 1761 in Graz as son of Imperial Count Weikhard Joseph von Trauttmansdorff-Weinsberg (1711-1788) and Countess Maria Anna von Wurmbrand-Stuppach (1733-1807).

He was ordained as Bishop of Hradec Králové on 8 September 1795.

Due to the imprisonment of Pope Pius VII by Napoleon Bonaparte, papal approval of this decision did not take place until 15 March 1814.

[3] He died in Vienna on 20 January 1819 and was buried in Olomouc.