Joachim Illies (March 23, 1925 - June 3, 1982) was a German biologist, entomologist, limnologist and author.
Joachim Illies studied biology at the University of Götting and Kiel.
He was the leader of the Max-Planck-Institute of limnology in Plön, where he worked for 31 years, an honorary professor for zoology at the University of Gießen, and editor-in-chief of the journal Aquatic Insects.
In addition to his scientific activities, as a councilor of the Evangelical Church in Germany he published around forty popular books on themes concerning anthropology and theology.
Illes became an authority on the Plecoptera of the Southern Hemisphere.