Michael Joseph Rossbach (12 February 1842, Heidingsfeld – 8 October 1894, Munich) was a German clinician and pharmacologist.
He studied medicine at the universities of Würzburg, Munich, Berlin and Prague, receiving his doctorate in 1865.
In 1869 he qualified as a lecturer in pharmacology at Würzburg, where in 1874 he became an associate professor.
In 1882 became a full professor of special pathology and therapy and director of the medical clinic at the University of Jena as a successor to Hermann Nothnagel.
In 1892 he resigned his professorship at Jena for reasons of health.His name is associated with "Rossbach's disease", a gastric disorder better known as hyperchlorhydria.