Strijen Castle, locally known as Kasteel Strijen or Slotbossche Toren, lies in a small park in the town of Oosterhout, in the province of Noord-Brabant in the Netherlands.
All that remains of the former Strijen Castle is a single tower fragment of seven storeys high.
The building of Strijen Castle probably started in 1288 by Willem Willemszoon van Strijen. Strangely enough the bailey was situated on the territory of the County of Holland and the castle itself on the territory of the Duchy of Brabant.
In 1324 the castle was bought by Willem van Duivenvoorde who reinforced and renovated it. When he died the castle became property of his half-brother Jan van Polanen.
In 1573, during the 80-Years war, the castle was destroyed after a siege by Spanish troops. It was never rebuild and fell into decay. In the next centuries the castle ruin was used as a quarry for stones which were used to repair roads and a church in and around the village of Oosterhout.