Otto Egon Lowenstein FRSE (1906–1999) was a German-born zoologist.
He began as a research student at the University of Birmingham, gaining a second PhD in 1937.
In that year he took a post as Assistant Lecturer in Zoology at Exeter University.
In 1938 he went to Glasgow University as a Lecturer under Prof Edward Hindle.
His proposers were Maurice Yonge, Charles Wynford Parsons, John Walton and George Wyburn.