diff --git a/include/osg/PrimitiveSet b/include/osg/PrimitiveSet
index 6ee96a4f2..3b0f18a92 100644
--- a/include/osg/PrimitiveSet
+++ b/include/osg/PrimitiveSet
@@ -24,6 +24,7 @@
 #include <osg/Vec3d>
 #include <osg/Vec4d>
 #include <osg/MixinVector>
+#include <osg/GL2Extensions>
 
 #include <osg/BufferObject>