I'm trying to define a tree structure in GORM. Here is my model: class Tree { String name Level rootLevel static hasOne = [rootLevel: Level] static hasMany = [levels: Level] static mappedBy = [levels:"parentTree"] } class Level { String name Tree parentTree Level parentLevel Set subLevels static belongsTo = [parentTree: Tree] static hasMany = [subLevels: Level] } Insertion seems to work fine, but when I can't load a Tree with many levels and sublevels. I guess I missed something in the relations: - the Tree should have a reference to the rootLevel (and optionally to all sublevels) - a Level should have a reference to its parent level, its sublevels and the global parent Tree Could you point me out the right direction to get a tree structure like this ? Thanks