diff --git a/AABB_tree/include/CGAL/AABB_traits.h b/AABB_tree/include/CGAL/AABB_traits.h
index 51082d19c0f..ad6834edc52 100644
--- a/AABB_tree/include/CGAL/AABB_traits.h
+++ b/AABB_tree/include/CGAL/AABB_traits.h
@@ -25,6 +25,7 @@
 #include <CGAL/license/AABB_tree.h>
 
 #include <CGAL/Bbox_3.h>
+#include <CGAL/Default.h>
 #include <CGAL/intersections.h>
 #include <CGAL/internal/AABB_tree/Has_nested_type_Shared_data.h>
 #include <CGAL/internal/AABB_tree/Is_ray_intersection_geomtraits.h>