diff --git a/src/mac/carbon/thread.cpp b/src/mac/carbon/thread.cpp
index a2fb9e43eb..007f7c67cf 100644
--- a/src/mac/carbon/thread.cpp
+++ b/src/mac/carbon/thread.cpp
@@ -45,6 +45,8 @@
 #include "wx/mac/uma.h"
 #endif
 
+#include "wx/mac/macnotfy.h"
+
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------