Friedrich Mohs (January 29, 1773 - September 29, 1839) was a German geologist/mineralogist.

Mohs, born in Gernrode, Germany, studied chemistry, mathematics and physics at the University of Halle and also studied at the Mining Academy in Freiberg, Saxony. After assuming the position of a foreman at a mine in 1801, Mohs he moved in 1802 to Austria, where he was employed in trying to identify the minerals in a private collection of a Banker. As part of this task, he started classifying minerals by their physical characteristics, in spite of their chemical composition, as had been was done traditionally.

This emphasis on physical characteristics was at odds with the prevailing chemical systematics. Minerals are now classified by chemical characteristics, but the physical properties are still useful in field examination.

In 1812, Mohs became professor in Graz; in 1818, professor in Freiberg, Saxony; in 1826, professor in Vienna. He created a hardness scale that is still used as Mohs scale of mineral hardness.

Mohs died during a trip to Italy in Agordo near Belluno.