Justus Mühlenpfordt (22 April 1911 – 2 October 2000) was a German nuclear physicist. He received his doctorate from the Technische Hochschule Carolo-Wilhelmina zu Braunschweig, in 1936. He then worked in Gustav Hertz's laboratory at Siemens. In 1945, he was sent to Institute G, near Sukhumi and under the directorship of Hertz, to work on the Soviet atomic bomb project. Released from Soviet Union, Mühlenpfordt arrived in East Germany in 1955. He was appointed director of the Institut für physikalische Stofftrennung of the Academy of Sciences, in Leipzig. From 1969 until his retirement in 1974, Mühlenpfordt was director of the Forschungsbereiches Kern- und Isotopentechnik der Akademie.