Lillö Ruin is the ruin of a medieval castle, located in Kristianstad municipality, Scania, Sweden.

A fortress was built there, probably as early as the late 13th century.

The fortress was gradually improved to become more of a castle, Lillöhus.

[2] In the war of 1657 - 1658 Denmark lost the province of Scania to Sweden and Lillöhus was demolished.

The fields and wetlands surrounding the ruin are rich in bird life.