diff --git a/Point_set_processing_3/include/CGAL/scanline_orient_normals.h b/Point_set_processing_3/include/CGAL/scanline_orient_normals.h
index 1a58a0dd09f..a5b26bfe938 100644
--- a/Point_set_processing_3/include/CGAL/scanline_orient_normals.h
+++ b/Point_set_processing_3/include/CGAL/scanline_orient_normals.h
@@ -26,6 +26,7 @@
 #ifdef CGAL_EIGEN3_ENABLED
 
 #include <Eigen/Dense>
+#include <Eigen/IterativeLinearSolvers>
 
 //#define CGAL_SCANLINE_ORIENT_VERBOSE