François Désiré Roulin (August 1796 – 5 June 1874) was a French naturalist, physician and illustrator born in Rennes.
Roulin visited South America from 1821 to 1828, becoming an expert on the natural history of the region. In 1824 he served as a physician on an expedition funded by the Colombian government to survey the Meta River, a tributary of the Orinoco River. While in South America, he performed exploratory nature studies in Colombia, Venezuela, Ecuador and Peru. Illustrations from his studies were used by Georges Cuvier (1769-1832) in Le Règne Animal.
After returning to France in 1829, he was sub-librarian and librarian of the Institut de France. He published numerous articles in the following magazines: Le Globe, Le Temps, La Revue des Deux Mondes and Le Magasin picturesque.
Roulin was son-in-law to politician Joseph Blin (1764-1834), and an uncle to mathematician Joseph Bertrand (1822-1900) and archaeologist Alexandre Bertrand (1820-1902).