diff --git a/include/osg/NodeCallback b/include/osg/NodeCallback
index d8fe51f8d..84c8280b0 100644
--- a/include/osg/NodeCallback
+++ b/include/osg/NodeCallback
@@ -6,6 +6,7 @@
 #define OSG_NODECALLBACK 1
 
 #include <osg/Referenced>
+#include <osg/ref_ptr>
 
 namespace osg {