diff --git a/src/osgPlugins/obj/obj.cpp b/src/osgPlugins/obj/obj.cpp
index 1a528786a..b9d2c1f14 100644
--- a/src/osgPlugins/obj/obj.cpp
+++ b/src/osgPlugins/obj/obj.cpp
@@ -16,6 +16,7 @@
 #include <fstream>
 #include <string>
 #include <stdio.h>
+#include <functional>
 
 #include "obj.h"