Schloss Rathsmannsdorf, Renaissance castle in Rathsmannsdorf, Germany

Schloss Rathsmannsdorf is a former prince-bishopric castle in Rathsmannsdorf, part of the market town of Windorf in the Passau district. It stands about 300 m southwest of the parish church of St. Ulrich. Prince-Bishop Urban von Trennbach had it rebuilt in 1578/79 as a four-wing complex; the south wing later collapsed. The grounds are a protected monument (file no. D-2-75-159-52).

The fortress of the Prince-Bishopric of Passau at the border with the Duchy of Bavaria received its first recorded mention around 1400. It later became an important administrative seat during Prince-Bishop rule.

Rathsmannsdorf was a Präfektur of the Prince-Bishopric of Passau, and under administrator Duke Ernst of Bavaria it briefly housed a high-stift regional court. That court was merged with the Landgericht Oberhaus in 1592. The name of the surrounding Hofmark survives in the village, and the former Schlossgut farmyard is remembered as a Bodendenkmal.

The complex stands about 300 metres southwest of St. Ulrich parish church in Rathsmannsdorf. The south wing has collapsed, so the four-winged layout is no longer complete; the surviving former stables hold an event hall of roughly 400 square metres. The site is a protected monument (file number D-2-75-159-52).

The south wing collapsed after the castle was converted into a brewery following its sale by the Bavarian state in 1803. This transformation for industrial use left permanent marks on the building's structure.