Johannes Dierauer (20 March 1842, in Berneck – 14 March 1920, in St.
Gallen) was a Swiss historian and librarian.
He studied history at the universities of Zürich, Bonn and Paris, receiving his doctorate at Zürich in 1868 with a dissertation on Trajan, titled Beiträge zu einer kritischen Geschichte Trajans.
From 1868 to 1907 he taught classes in history at the cantonal school in St.
Gallen, and from 1874 onward, was head of the Stadtbibliothek Vadiana, the municipal library in St.