Burg Maissau, Medieval castle in Maissau, Austria.

Burg Maissau is a medieval castle in Maissau featuring two distinct building sections with different architectural styles. The southern wing has been renovated in Romanesque-Neo-Gothic style, while the older section dates to the 15th century and displays early Gothic characteristics.

The castle is first documented in 1122, when Rudolf and Rozinus of Maissau are named. The Maissau family died out in 1440 with Otto IV, and the castle passed by inheritance to the Eckartsau family. Their descendant Magdalena von Zelking inherited the lordship in 1526 and married Sebastian von Traun, so the Abensperg and Traun family has owned it without interruption since 1526. In 1645 Swedish troops took the castle and the fortified town; in 1653 the family was raised to the rank of Imperial Count.

The Gothic hall on the ground floor dates from the 14th century and has served as a chapel since 1964. Visitors can experience both the original architecture and how it has been repurposed for worship.

The castle courtyard opens only during the first Advent weekend for the traditional Advent celebration. This is the primary opportunity for public access to visit the grounds.

The two heraldic reliefs beside the gate tower carry dates: the Abensperg-Traun alliance coat of arms is marked 1563, the Traun-Polheim one 1583, and a central cartouche 1460. The hexagonal spiral staircase tower at the northwest approach to the upper castle bears the date 1879.