Osann is a surname of German origin. Notable people with the surname include:
Emil Osann (1787–1842), German physician and physiologist Friedrich Gotthilf Osann (1794–1858), German classical philologist, brother of Emil and Gottfried Gottfried Osann (1796–1866), German chemist and physicist, brother of Emil and Friedrich Kate Osann, American cartoonist
See also Osann-Monzel, a municipality in Rhineland-Palatinate, Germany