Paul Julius Arndt (14 October 1865 – 17 July 1937) was a German classical archaeologist who was a native of Dresden.
He studied classical art under Johannes Overbeck (1826-1895) at the University of Leipzig, and classical archeology with Heinrich Brunn (1822-1894) at the University of Munich. In 1887 he graduated with a dissertation on Greek vases, and subsequently worked as an assistant to Heinrich Brunn in Munich. Following Brunn's death in 1894, Arndt became an assistant to Adolf Furtwängler (1853-1907), and was responsible for edition of Denkmäler griechischer und römischer Skulptur.
Arndt was the son of a wealthy merchant in Mecklenburg, and for much of his career was financially independent, and was able to work as a private scholar and dealer of Greek art. He was primarily known as a collector of ancient sculptures, a large part of which today are kept in the Glyptothek of Munich, and in Ny Carlsberg Glyptotek, Copenhagen. He also amassed a superb collection of ancient gems that since 1958 have been part of the Staatlich Münzsammlung in Munich. Arndt's scientific estate is presently owned by the Institute of Classical Archaeology of the University of Erlangen.