Wilhelm Dunker, full name Wilhelm Bernhard Rudolph Hadrian Dunker (21 February 1809, Eschwege – 13 March 1885, Marburg) was a German geologist, paleontologist and zoologist (specifically a malacologist).
Wilhelm Dunker studied mining and metallurgical engineering in Göttingen and worked at first as a trainee with the local mining authority. Soon thereafter he was appointed a teacher of mineralogical sciences at the poly-technical school in Kassel. In 1854 he was appointed professor at the University of Marburg, at which he taught up to his death. Dunker was one of the most important malacologists of his time. He had a very extensive private collection of snails and shells, which he constantly increased by exchange with other collectors (and probably also by purchases). He maintained contacts with his contemporaries Rudolph Amandus Philippi, Ludwig Karl Georg Pfeiffer, Hugh Cuming and Johannes Albers. By exchange he also acquired numerous original specimens and types from these authors.
After his death, Dunker's mollusc collection was purchased by the Prussian state and placed in the Museum für Naturkunde in Berlin, under the curatorship of Eduard von Martens, where it remains to this day. Wilhelm Dunker wrote a large number of scientific publications on the systematics of the Mollusca and described numerous new species. In the year 1846, together with Hermann von Meyer, he founded the magazine "Palaeontographica".