Weidenau is a suburban part (Stadtteil) of the city Siegen in Germany.
Weidenau, a northern part of Siegen, shares borders with Niedersetzen in the north, Geisweid in the north-west, the central part of Siegen in the south, Birlenbach in the west, Bürbach in the south-east and Dreis-Tiefenbach, a part of the city of Netphen in the north-east.
The University of Siegen is located in Weidenau.