Gustav Wilhelm Frank (25 September 1832, in Schleiz – 24 September 1904, in Hinterbrühl) was a German-Austrian Protestant theologian, known as the author of a multi-volume work on the history of Protestant theology.
He studied theology at the University of Jena, where his influences included Karl von Hase.
In 1859 he obtained his habilitation, and in 1864 became an associate professor at Jena.
In 1867 he was appointed a full professor of systematic theology at the University of Vienna.
In 1867 he also became a member of the Austrian Protestant Church Council.In his work, he was concerned with dogmatic-historical issues.
He was a representative of philosophical rationalism, and as such, an opponent of religious Supranaturalism.