Hans Fruhstorfer (7 March 1866 Passau, Germany – 9 April 1922 in Munich) was a German explorer, insect trader and entomologist who specialised in Lepidoptera. He collected and described new species of exotic butterflies, especially in Seitz's Macrolepidoptera of the World. He is best known for his work on the butterflies of Java.His career began in 1888 when he spent two years in Brazil. The expedition was financially successful and led to his becoming a professional collector.