diff --git a/wxPython/src/helpers.cpp b/wxPython/src/helpers.cpp
index 6a196331a3..13f93b78c3 100644
--- a/wxPython/src/helpers.cpp
+++ b/wxPython/src/helpers.cpp
@@ -223,11 +223,13 @@ PyObject* __wxStart(PyObject* /* self */, PyObject* args)
 
 void __wxCleanup() {
     wxEntryCleanup();
+#ifdef WXP_WITH_THREAD
     delete wxPyTMutex;
     wxPyTMutex = NULL;
     wxPyTStates->Empty();
     delete wxPyTStates;
     wxPyTStates = NULL;
+#endif
 }