diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/extrude.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/extrude.h
index 61666f5d155..2b3ecaceb84 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/extrude.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/extrude.h
@@ -31,7 +31,7 @@
 #include <CGAL/boost/graph/named_function_params.h>
 #include <CGAL/boost/graph/copy_face_graph.h>
 #include <CGAL/Kernel_traits.h>
-#include <boost/unordered_map.hpp>
+#include <vector>
 
 namespace CGAL {
 namespace Polygon_mesh_processing {