Ottmar von Mohl (17 January 1846 – 23 March 1922) was a German diplomat and government adviser in Meiji period Japan.
Ottmar von Mohl, born in Tübingen, Germany was the son of famous jurist Robert von Mohl. He studied law at the University of Tübingen, passed the first Baden State Examination in 1868 and earned a doctorate in law from the University of Heidelberg the same year. In 1873, he was appointed cabinet secretary of Empress Augusta of Saxe-Weimar.