Glenn Lowell "Jep" Jepsen (4 March 1903 – 15 October 1974) was an American paleontologist and professor of vertebrate paleontology at Princeton University.
He collected and described many fossil species particularly from the Oligocene of the Badlands of South Dakota and the Paleocene of Polecat Bench, Wyoming.
Here he became deeply interested in fossils, collecting from the Oligocene deposits in the Badlands where he met William J. Sinclair.
During the same year, he discovered fossils of Late Triassic fishes when digging for the foundation of the new Firestone Library of the Princeton University.
He helped organize the first international conference on genetics, paleontology and evolution which resulted in a volume co-edited with George Gaylord Simpson and Ernst Mayr.