diff --git a/include/osg/Shader b/include/osg/Shader
index c17547ba7..486e98707 100644
--- a/include/osg/Shader
+++ b/include/osg/Shader
@@ -37,6 +37,8 @@ namespace osg {
   * configuration.
   */
 
+class Program;
+
 class OSG_EXPORT Shader : public osg::Object
 {
     public: