diff --git a/include/wx/osx/setup0.h b/include/wx/osx/setup0.h
index d3a72de273..f9f1e7c952 100644
--- a/include/wx/osx/setup0.h
+++ b/include/wx/osx/setup0.h
@@ -1439,6 +1439,10 @@
 // Compile wxUIActionSimulator class?
 #define wxUSE_UIACTIONSIMULATOR 1
 
+// This is only used under Unix, but needs to be defined here as it's checked
+// by wx/unix/chkconf.h.
+#define wxUSE_XTEST 0
+
 // ----------------------------------------------------------------------------
 // wxDC classes for various output formats
 // ----------------------------------------------------------------------------