Carl Hunstein (1843 – March 13, 1888) was a German ornithologist and plant collector.
Hunstein was born in Homberg, Germany. He emigrated to America, then relocated to New Zealand. From 1885 until his death, he was employed by the German New Guinea Company.
He was a successful discoverer of new species of birds-of-paradise, such as the:
Hunstein lost his life when a tsunami, caused by an submarine volcano, hit the coast of New Britain of the Bismarck Archipelago.
He is commemorated in New Guinea by the Hunstein Mountains and the Hunstein Forest, and in plants and animals including the Hunstein's mannikin (Lonchura hunsteini), Cyathea hunsteiniana and Araucaria hunsteinii.