Carl Chun or Karl Friedrich Gustav Chun (German pronunciation: [ˈkuːn]; 1 October 1852 – 11 April 1914) was a German marine biologist who worked as a professor at the Universities of Königsberg (1883), Breslau (1891) and Leipzig (1898). He was a pioneer of German oceanographic research, organizing the first deep-sea expedition aboard the SS Valdivia in 1898-99. He spent much of his life studying the collections made during the expedition, and was responsible for discovering many marine organisms, including the vampire squid.