diff --git a/xpcom/tests/TestRegistrationOrder.cpp b/xpcom/tests/TestRegistrationOrder.cpp
index 382cdec2d1e..8c78cff8b69 100644
--- a/xpcom/tests/TestRegistrationOrder.cpp
+++ b/xpcom/tests/TestRegistrationOrder.cpp
@@ -38,7 +38,6 @@
  * ***** END LICENSE BLOCK ***** */
 
 #include "TestHarness.h"
-#include "nsStringAPI.h"
 #include "nsILocalFile.h"
 #include "nsIDirectoryService.h"
 #include "nsDirectoryServiceDefs.h"