Marsvinsholm Castle, Renaissance castle in Ystad Municipality, Sweden

Château de Marsvinsholm is a rectangular castle near Ystad featuring Dutch Renaissance architecture with a distinctive four-story central structure. Two five-story towers anchor opposite corners of the building, and the entire structure sits on an artificial island in a small lake.

The estate, known as Bosøe and Borsøe, is recorded from the 14th century and passed to the Danish crown under Valdemar Atterdag. Otte Marsvin bought it in 1630 and built the present castle in 1644–1648 on beech poles in a small lake, naming it after his family. Erik Ruuth renovated it in 1782–1786, and in 1856–1857 Jules Sjöblad had architect Ch. F. Zwingmann restore it in the Dutch Renaissance style of Christian IV.

The name comes from Otte Marsvin, who built the castle in 1644–1648: marsvin is Danish for porpoise and holm for a small island. His sister Ellen Marsvin was the mother-in-law of King Christian IV of Denmark. The estate was first recorded in the 14th century as Bosøe or Borsøe.

The castle is privately owned and can only be viewed from the exterior in designated areas. Visitors should stick to public viewpoints and respect the boundaries of the private property.

In 1667, during the Swedish-Danish wars of the 17th century, the castle was seized by snapphanar, pro-Danish guerrillas fighting the Swedish crown. The episode is one of several moments when the building stood at the centre of the Scanian conflict.