diff --git a/extensions/pref/system-pref/src/nsSystemPref.h b/extensions/pref/system-pref/src/nsSystemPref.h
index f44bfc145057..bfae6ad9ad7a 100644
--- a/extensions/pref/system-pref/src/nsSystemPref.h
+++ b/extensions/pref/system-pref/src/nsSystemPref.h
@@ -45,7 +45,6 @@
 #include "nsCOMPtr.h"
 #include "nsXPCOM.h"
 #include "nsCRT.h"
-#include "nsIRegistry.h"
 #include "nsIAppStartupNotifier.h"
 #include "nsICategoryManager.h"
 #include "nsIServiceManager.h"