Karl Friedrich Heusinger (28 February 1792 – 5 May 1883) was a German pathologist who was a native of Farnroda.
He studied medicine in Jena and Marburg, and afterwards was an assistant to Karl Gustav Himly (1772–1837) at the University of Göttingen.
In 1813 he served as a military doctor in the Prussian Army, and later was a professor at the Universities of Jena (from 1821), Würzburg (from 1824) and Marburg (1829–83).
Heusinger was a pioneer in the field of comparative pathology.
In 1829 he published an influential work on physical and psychological anthropology titled GrundriĂź der physischen und psychischen Anthropologie.
He also wrote a remarkable review of geophagy, titled Die sogenannte Geophagie oder tropische (besser: Malaria-) Chlorose als Krankheit aller Länder und Klimate.