Paul Friedländer (29 August 1857 – 4 September 1923) was a German chemist best known for his research on derivates of indigo (for example thioindigo) and isolation of Tyrian purple from Murex brandaris.

He left the well-equipped laboratories of Baeyer in Munich in 1884 to work in the small company K. Oehler in Offenbach.

His research on the color variations in substituted indigoes yielded numerous patents and was applied in industrial production.

During World War I, Friedländer worked at the Kaiser Wilhelm Institute for Physical Chemistry and Elektrochemistry together with Fritz Haber.

The poor living standards after the war affected his health, and after a trip in the summer of 1923 from Darmstadt to Biebrich, Friedländer had to stay in a hospital.