Constantin Freiherr von Ettingshausen (or Baron Constantin von Ettingshausen) (June 16, 1826 – February 1, 1897) was an Austriangeologist and botanist.
Ettingshausen was born in Vienna. He graduated as a doctor of medicine in Vienna, and became in 1854 professor of botany and natural history at the medical and surgical military academy in that city. In 1871 he was chosen professor of botany at Graz, a position which he occupied until the close of his life. He was distinguished for his researches on the Tertiaryfloras of various parts of Europe, and on the fossil floras of Australia and New Zealand. He died at Graz.
Die Farnkruter der Jetztwelt zur Untersuchung and Bestimmung der in den Formationen der Erdrinde eingeschiossenen Uberreste von vorweltlichen Arten dieser Ordnung nach dem Flchen-Skelet bearbeitet (1865)
Physiographie der MedicinalPflanzen (1862)
A Monograph of the British Eocene Flora (with J. Starkie Gardner), Palaeontograph. Soc. vol. i. (Filices, 1879 1882)