Johann Otto Leonhard Heubner (January 21, 1843 – October 17, 1926) was a German internist and pediatrician who was a native of Mühltroff.
He studied medicine at the University of Leipzig, and in 1867 became an assistant to Carl Reinhold August Wunderlich (1815–1877) at Leipzig.
He later founded a children’s hospital and clinic in Leipzig, and in 1891 was appointed to the chair of pediatrics.
With Eduard Heinrich Henoch (1820–1910), he was among the first to use an antitoxin for diphtheria that had recently been developed by Emil von Behring (1854–1917).
Heubner also made contributions in his research of cerebrospinal meningitis.
He provided an early description of syphilitic endarteritis obliterans, a condition that is sometimes referred to as "Heubner's disease".