The Counts of Vianden, ancestors of the House of Orange-Nassau, were associated with the castle of Vianden (Vianden Castle) in Luxembourg.
In the 12th to 15th centuries the counts of Vianden were the mightiest lords of the area between the rivers Rhine, Mosel and Maas. Their territory was in modern Vianden canton, Luxemburg and Bitburg-Prüm, Germany.
One recognition of their importance was that Henry I of Vianden (c. 1200–1252) in 1216 married Margaret, Marchioness of Namur (c. 1194–1270) of the Capetian House of Courtenay, and daughter of Peter II of Courtenay (1167–1217), emperor of Constantinople. It was the peak of its power, but in 1264 Vianden became a vassal to the counts of Luxembourg. Godefroid I participated in the Battle of Worringen in 1288 as a vassal to the Duchy of Brabant. The male line of the ruling house of Vianden became extinct in 1337.