diff --git a/include/wx/buffer.h b/include/wx/buffer.h
index 1144aa420d..7d362ee841 100644
--- a/include/wx/buffer.h
+++ b/include/wx/buffer.h
@@ -162,7 +162,7 @@ private:
 
     // placeholder for NULL string, to simplify this code
     // NB: this is defined in string.cpp, not (non-existent) buffer.cpp
-    static Data NullData;
+    static WXDLLIMPEXP_DATA_BASE(Data) NullData;
 
     void IncRef()
     {