Otto Magnus Freiherr[1] von Stackelberg (25 July 1786 – 27 March 1837) was a Baltic German, Imperial Russian archaeologist, as well as a writer, painter and art historian.

He was born in Reval (Tallinn), Estonia to Otto Christian Engelbrecht von Stackelberg and Anna Gertruda Düker.

His mother, recognising talent in his early drawings, arranged for the German painter Reus to come to the family estate at Fähna (Vääna) to act as Otto's tutor.

After wintering in Geneva he continued with his brother Karl to Italy, where the initial thoughts he had had at Zurich of devoting his life to the arts flourished.

He travelled to Italy again in 1816, researching antiquity and the Middle Ages as an art historian and becoming co-founder of the "Instituto Archeologico Germanico" in Rome.

Together with Eduard Gerhard, August Kestner and Theodor Panofka, he also established in 1824 the "Hyperboreans" ("Römischen Hyperboraeer") there, a group of northern European scholars who studied classical ruins.