Diepold III, Margrave of Vohburg (c. 1079 – 1146) was a Bavarian noble from the House of the Diepoldinger-Rapotonen.
[1] The scattered inheritance included the Margraviates of Cham and Vohburg as well as possessions in the Chiemgau, in Swabia and in Lower Austria.
He continued the land development in Egerland through forest clearing, founding of villages and the settlement of German colonists that his father had started.
With Adelaide of Poland (daughter of Władysław I Herman and Judith of Swabia) he had 5 children, among them Diepold IV who already died before him in 1130, and the daughter Adelheid of Vohburg who married Emperor Frederick I one year after her father's death.
His third marriage was to Sophia, the sister of a Hungarian count named Stephan (Istvan).