Count Ernst Johann von Stackelberg (Russian: Эрнест Густавович Штакельберг) (1813 – 30 August 1870) was a Baltic German military figure and diplomat.

For his service, Stackelberg was promoted to the rank of podporuchik and then transferred to the office of War Minister Alexander Chernyshyov as adjutant.

Stackelberg was first placed under the command of Lieutenant General Apollon Galafeyev and took part in the Battle of the Valerik River with the Chechens in Chekhinsky Forest.

For his outstanding service, Stackelberg was promoted to the rank of staff captain and awarded with the Order of Saint Vladimir, 4th Class.

In 1861, he was appointed envoy extraordinary and minister plenipotentiary to Spain and then sent to Italy in the same capacity a year later.