Walther Hermann Richard Horn (19 October 1871 – 10 July 1939) was a German entomologist who specialised in beetles (Coleoptera).
He was born in Berlin, where he also died.
He is not to be confused with the American entomologist George Henry Horn, another entomologist that studied Coleoptera.
Walther Horn was first a physician then the director of the German Entomological Institute.