Wilhelm Daniel Joseph Koch was a German physician and botanist from Kusel, a town in the Rhineland-Palatinate.
Koch studied medicine at the Universities of Jena and Marburg, and afterwards was a Stadtphysicus in Trarbach and Kaiserslautern. In 1824 he became a professor of medicine and botany at the University of Erlangen, where he stayed for the remainder of his life. At Erlangen, he was also director of the botanical gardens. In 1833, he was elected a foreign member of the Royal Swedish Academy of Sciences.
Among his better written efforts was a synopsis on German and Swiss flora titled Synopsis florae germanicae et helveticae. Another noteworthy publication of his was Catalogus plantarum, quae in ditione Florae Palatinatus.
He died in Erlangen.
He has been honoured in the naming of 2 plant genera; Eokochia, and Kochia.