diff --git a/src/gtk/window.cpp b/src/gtk/window.cpp
index 4178eddb57..0dbcab70d2 100644
--- a/src/gtk/window.cpp
+++ b/src/gtk/window.cpp
@@ -2081,6 +2081,16 @@ wxWindow *wxGetActiveWindow()
 }
 
 
+// Under Unix this is implemented using X11 functions in utilsx11.cpp but we
+// need to have this function under Windows too, so provide at least a stub.
+#ifdef __WINDOWS__
+bool wxGetKeyState(wxKeyCode WXUNUSED(key))
+{
+    wxFAIL_MSG(wxS("Not implemented under Windows"));
+    return false;
+}
+#endif // __WINDOWS__
+
 wxMouseState wxGetMouseState()
 {
     wxMouseState ms;