Richard Harlan (September 19, 1796 – September 30, 1843) was an American naturalist, zoologist, herpetologist, physicist, and paleontologist. He was the author of Fauna Americana (1825) and American Herpetology.
Harlan was born in Philadelphia, to Joshua Harlan, a wealthy Quaker merchant, and his wife Sarah, one of their ten children. He was three years older than his brother Josiah Harlan, who would become the first American to visit Afghanistan and who was the presumed inspiration for Rudyard Kipling's story The Man Who Would Be King. He graduated in medicine from the University of Pennsylvania taking time off during his studies to spend a year at sea as a ship's surgeon for the British East India Company. In 1821 he was elected professor of comparative anatomy in the Philadelphia museum. One of his passions was the collection and study of human skulls. At its peak, his collection contained 275 skulls, the largest such collection in America. He died of apoplexy in New Orleans, Louisiana.
In 1834, Harlan described and named Basilosaurus ("king lizard"), a genus of early whale, erroneously assuming he had found a Plesiosaurus-like dinosaur.