Henry Fairfield Osborn, Sr. FRS (August 8, 1857 – November 6, 1935) was an American paleontologist, geologist and eugenics advocate. He was professor of anatomy at Columbia University, president of the American Museum of Natural History for 25 years and a cofounder of the American Eugenics Society.
Among his significant contributions include naming the dinosaurs Tyrannosaurus and Velociraptor, his widely used system of names for dental cusps and other features of mammalian teeth, as well as his research on fossil proboscideans (elephants and their extinct relatives).