The House of Dönhoff (Polish: Denhoff, sometimes also Doenhoff) was an old and influential German noble family, which later also became part of the Polish nobility.
It was first mentioned in 1282, in the County of Mark in Westphalia. Their original seat was Dönhof near Witten which remained in the family until 1463. From 1303 until the 16th century a property called Dönhoff near Wetter (Ruhr) was also owned by the family.
Younger sons of the family served as knights of the Teutonic Order and acquired property in the Baltic State of the Teutonic Order: In 1410 Godecke von Dönhoff (d. before 1444) owned the estate of Allo in Estonia, in 1478 Hermann von Dönhof was granted land in Livonia. In the 16th century, a branch became recognized as szlachta (Polish nobility) in the Polish–Lithuanian Commonwealth.
After the secularization of the State of the Teutonic Order during the Protestant Reformation in 1525, the East Prussian branch served the House of Hohenzollern in its newly acquired Duchy of Prussia. This branch owned Friedrichstein Palace from 1666 until 1945.
In 1633 all branches of the family were created imperial counts. In 1637 one of the Polish Denhoff branches was granted the title of Imperial Prince, which was later extinguished.