Dietrich Herrman Reinhard von Schlechtendal dr. (20 October 1834, Halle – 5 July 1916) was a German entomologist who worked on Cynipidae.
von Schlechtendal trained as a mining expert and metallurgist. He worked for many years as an assistant at the Geologisch-Mineralogischen Institut in Halle. His botanical knowledge led to study of gall wasps . Working with the North American species Neuroterus quercus-batatus (Fitch) in a laboratory he bred from the parthenogenetic females the bi-sexual form. This species was then introduced onto Turkey oaks in the Halle Botanic Garden. The up to then sterile over decades trees produced fertile seeds (Hüsing, 1966).
Many species of Cynipidae were described by von Schlechtendal or their generation sequence was clarified. His collection of Cynipidae with their galls is shared by the Museum für Naturkunde in Berlin and the Zoological Institute of the University of Halle-Wittenberg which also conserves his collections of Blattidae and Lepidoptera. Dietrich von Schlechtendal was an honour member of the Entomological Society of Halle and a member of the Stettin Entomological Society.
As well as many short scientific papers he wrote Die Gallbildungen (Zoocecidien) der Deutschen Gefässpflanzen, 1891, R. Zückler. Zwickau (1891).