Rothschildschloss, Medieval castle and museum in Waidhofen an der Ybbs, Austria.

Rothschildschloss is a castle and museum in Waidhofen an der Ybbs, built around a courtyard on a conglomerate rock above the Ybbs. Its 33-metre, nine-storey keep from the second half of the 14th century carries a glass addition from 2006. The courtyard is framed by a neo-Gothic arcade with pointed arches on the ground floor and round arches above.

The castle's core dates from the first half of the 13th century, when it served as the seat of the Freising stewards. From 1875, Albert Salomon Anselm von Rothschild used it to administer his estates and had it rebuilt in neo-Gothic style with Vienna cathedral architect Friedrich von Schmidt. The town acquired it later and renovated it until 2007 under architect Hans Hollein.

The museum inside the castle is the 5e-Museum, opened after the 2007 renovation and devoted to the history of Waidhofen an der Ybbs. Its name refers to the five elements, and the displays link the town's development to ironworking in the Ybbs valley. The castle itself served as one of the two venues of the 2007 Lower Austrian state exhibition.

The site has a restaurant serving regional Mostviertler cuisine and international dishes with weekday operations. Visitors should note that certain days are reserved for private events.

The medieval frescoes were uncovered in 1878 on the walls of the former castle chapel, not in the residential hall. The best-preserved figures of saints, Church Fathers and music-making angels, probably by an Upper Italian artist, were detached in 1922 and remounted on a rebuilt arch at the start of the middle staircase.