Gustav Philipp Hermann Brandes (2 May 1862 – 17 July 1941) was a German zoologist who specialized in parasitology.
Brandes was born at Schoningen near Helmstedt where his father Carl (1829-1905) worked as a cashier.
He was in Freiburg for military service following which he began to study botany from 1884 and attend lectures by August Weismann.
In 1886 he joined the University of Leipzig and received a doctorate in 1888 for a dissertation on the Holostomeae under Rudolf Leuckart.
In 1933, he was a signatory to the Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State.