Ludwig Derleth (3 November 1870 – 13 January 1948) was a German writer.
He was born in Gerolzhofen in Bavaria.
After studying philosophy and literature Derleth worked as a college level teacher of ancient languages.
While living in Munich he became part of the Stefan George entourage and also the Munich Cosmic Circle of Alfred Schuler and Ludwig Klages, which broke up in 1904.
In later years he made his living as a free-lance writer in Rome, Basel, Perchtolfsdorf outside Vienna and, from 1935, in Ticino, where he died in 1948.