Ottokar Chiari (February 1, 1853 – May 12, 1918) was an Austrian laryngologist and professor at the University of Vienna who was a native of Prague.
At Vienna he was an assistant to Leopold von Schrötter (1837–1908), and later succeeded Karl Stoerk (1832–1899) as director of the laryngological clinic. He was the son of gynecologist Johann Baptist Chiari (1817–1854), and younger brother to pathologist Hans Chiari (1851–1916).
Ottokar Chiari was a specialist in the field of rhinolaryngology, and is credited for advancing new surgical procedures at the laryngological clinic in Vienna. In 1912 he introduced the "transethmoidal approach", which is a type of ethmoidectomy for treatment of sinus-related diseases and conditions.
In 1932 Chiarigasse in Favoriten-Vienna was named in his honour.