diff --git a/src/gui/accessible/qaccessible.h b/src/gui/accessible/qaccessible.h
index 66cd067ace..a0281d1c11 100644
--- a/src/gui/accessible/qaccessible.h
+++ b/src/gui/accessible/qaccessible.h
@@ -396,7 +396,7 @@ public:
     static UpdateHandler installUpdateHandler(UpdateHandler);
     static RootObjectHandler installRootObjectHandler(RootObjectHandler);
 
-    class ActivationObserver
+    class Q_GUI_EXPORT ActivationObserver
     {
     public:
         virtual ~ActivationObserver();