Heinrich Ernst Karl Jordan (7 December 1861 – 12 January 1959) was a German-British entomologist.

[1] Jordan was born in a farming family in Almstedt, raised by an uncle after the death of his father in 1855, finished school in Hildesheim and educated at Göttingen University.

[2] In 1893 he began work at Walter Rothschild's Natural History Museum at Tring, specialising in Coleoptera, Lepidoptera and Siphonaptera.

Jordan is commemorated in the scientific name of a species of African lizard, Karusasaurus jordani.

[3] In 1972, the Lepidopterists' Society began to award the Karl Jordan Medal in his honour.