Schloss Ebenzweier, Protected heritage château in Altmünster, Austria.

Schloss Ebenzweier is a castle in Altmünster with architectural elements spanning from medieval times through the 19th century, located near Lake Traunsee in Austria. The multi-story structure displays stone facades with tower features and masonry work that reveal layers of construction and modification across centuries.

The estate was held by the Schachner family, documented from 1292 with Ditmayr Schachner, and was called Schachnerhof under Paul Schachner in 1380. After the Protestant Schachners lost it in 1626, it passed through the Zedlitz, Rohrbach and Seeau families, who enlarged the old castle. Archduke Maximilian Joseph d'Este, who bought it in 1830, had it restored and rebuilt as a country seat; he died there on 1 June 1863.

The name Ebenzweier comes from the site's position "neben dem Weiher", beside the pond, earlier written Nebenzweier; the Schachners already used Schachen and Nebenzweier interchangeably. In the front courtyard stands an octagonal stone fountain trough with carved coats of arms and a column bearing a stone figure of St Florian. The castle chapel keeps a carved door of 1633 and an altar from around 1660.

Schloss Ebenzweier stands at Ebenzweier Nr. 17 in Altmünster, not on a street of that name; the grounds run from the building down to the Traunseebundesstraße on the Traunsee shore. The complex now houses a hospitality vocational school with an attached boarding school, so the interiors are in school use. The landscaped park, laid out under Archduke Maximilian Joseph d'Este, is the part a passer-by can walk through.

The castle received protected heritage status and carries registration number 36956, a designation that ensures its long-term preservation under Austrian law. This official recognition matters to visitors because it confirms that the building's historical integrity remains safeguarded.