Philippe-Louis Voltz (15 August 1785 – 6 February 1840) was a French mining engineer, metallurgist, and geologist.
He examined fossils in relation to stratigraphy and, with his knowledge of languages, took part in the interchange of ideas between French and German geologists.
He studied steel making in England and Germany and worked on blast furnaces in France.
From 1830 he gave lectures in geology at Strasbourg where he influenced many future geologists including Jules Thurmann and Amanz Gressly.
Along with Armand Dufrénoy (1792-1857), he was also involved in arranging the geological collections with a stratigraphic focus at the Strasbourg Academy and brought together numerous fossil plants, some described by his student Wilhelm Philippe Schimper.