Franz-Joseph Müller Freiherr von Reichenstein or Franz-Joseph Müller von Reichenstein (1 July 1740 or 4 October 1742 - 12 October 1825 or 1826) is an Austrian mineralogist and mining engineer.

Müller holds several positions in the Austria-Hungarian administration of mines and coinage in the Banat, Transylvania, and Tyrol.

During his time in Transylvania, he discovers tellurium in 1782.

In his later career, he becomes member of the imperial council in Vienna and is knighted to the rank of an Freiherr in 1820.