Eduard Heinrich Graeffe or Gräffe (27 December 1833, Zurich – 23 April 1916 Ljubljana) was a Swiss zoologist and naturalist. As an entomologist, he specialised in Hymenoptera, Diptera and Hemiptera.
From around 1860, Graeffe was in the employ of Johann Cesar VI. Godeffroy, a wealthy shipping magnate from Hamburg. Graeffe was hired in order to organize Godeffroy's natural history collection as a scientific museum, the "Museum Godeffroy".[1][2][3] From 1862 to 1873, he was based in Samoa,[2] conducting scientific research and collecting specimens from throughout the South Pacific. Among his writings of the expedition was: Reisen im Innern dei Insel Viti Levu (in: Neujahrsblatt der Naturforschende Gesellschaft in Zürich auf das Jahr 1868, Nr. 70).[4]
From 1875 to 1898, he worked as an inspector at the Zoological Station in Trieste.[5] The Fiji whistler (Pachycephala graeffii) is named in honor,[6][7] as is Arthrocormus graeffii, a botanical species described by German bryologist Karl Müller.[8]