Paul Stein (1852–1921) was a German museum curator and entomologist . He specialised in Diptera especially the family Anthomyiidae. In this group he studied the world fauna describing many new genera and species. Stein worked with Theodor Becker, Mario Bezzi and Kálmán Kertész on Katalog der Paläarktischen dipteren (1903 onwards) published in Budapest from 1903.His collection is in the Museum für Naturkunde in Berlin.