Ferdinand Anton Franz Karsch or Karsch-Haack (2 September 1853 in Münster – 20 December 1936 in Berlin) was a German arachnologist, entomologist and anthropologist. The son of a doctor, Karsch was educated at the Friedrich Wilhelm University in Berlin and published a thesis on the gall wasp in 1877. From 1878 to 1921 he held the post of curator at the Museum für Naturkunde Berlin. Between 1873 and 1893, he published a catalogue of the spiders of Westphalia: he also published numerous articles on the specimens that the museum received from various explorers and naturalists working in Africa, in China, in Japan, in Australia, etc. This publication of others' work sometimes led to disputes over priority and nomenclature, for example with Pickard-Cambridge.