Ottmar von Mohl (17 January 1846 – 23 March 1922) was a German diplomat and government adviser in Meiji period Japan.

His diplomatic career led him to Cincinnati, Ohio,[1] in the United States in 1879 and to Saint Petersburg, Russia, in 1885 as German consul.

He was recruited by the Meiji period Japanese government as a foreign adviser from 1887 to 1889.

He and his wife, Wanda von Mohl (née Countess von der Groeben), served with the Japanese Imperial Household Ministry in Tokyo, Japan, to introduce European Court ceremonials and protocols to Japanese Emperor Meiji and his court.

From 1897 to 1917, he served as a German delegate to the Egyptian National Debt Commission in Cairo, until the activities of that Commission were suspended in 1914 due to the Egyptian Declaration of War.