diff --git a/Include/pythonrun.h b/Include/pythonrun.h
--- a/Include/pythonrun.h
+++ b/Include/pythonrun.h
@@ -211,6 +211,8 @@ PyAPI_FUNC(void) PyByteArray_Fini(void);
 PyAPI_FUNC(void) PyFloat_Fini(void);
 PyAPI_FUNC(void) PyOS_FiniInterrupts(void);
 PyAPI_FUNC(void) _PyGC_Fini(void);
+
+PyAPI_DATA(int) _Py_Finalizing;
 #endif
 
 /* Stuff with no proper home (yet) */
diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -440,6 +440,13 @@ PyEval_RestoreThread(PyThreadState *tsta
     if (gil_created()) {
         int err = errno;
         take_gil(tstate);
+        /* _Py_Finalizing is protected by the GIL */
+        assert(main_thread);
+        if (_Py_Finalizing && PyThread_get_thread_ident() != main_thread) {
+            drop_gil(tstate);
+            PyThread_exit_thread();
+            assert(0);  /* should never be reached */
+        }
         errno = err;
     }
 #endif
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -93,6 +93,8 @@ int Py_IgnoreEnvironmentFlag; /* e.g. PY
 int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
 int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
 
+int _Py_Finalizing = 0;
+
 /* PyModule_GetWarningsModule is no longer necessary as of 2.6
 since _warnings is builtin.  This API should not be used. */
 PyObject *
@@ -191,6 +193,7 @@ Py_InitializeEx(int install_sigs)
     if (initialized)
         return;
     initialized = 1;
+    _Py_Finalizing = 0;
 
 #if defined(HAVE_LANGINFO_H) && defined(HAVE_SETLOCALE)
     /* Set up the LC_CTYPE locale, so we can obtain
@@ -395,6 +398,10 @@ Py_Finalize(void)
      * the threads created via Threading.
      */
     call_py_exitfuncs();
+
+    /* Now all non-main threads will automatically exit when trying to take
+       the GIL. */
+    _Py_Finalizing = 1;
     initialized = 0;
 
     /* Flush stdout+stderr */
diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
--- a/Python/thread_pthread.h
+++ b/Python/thread_pthread.h
@@ -244,9 +244,9 @@ void
 PyThread_exit_thread(void)
 {
     dprintf(("PyThread_exit_thread called\n"));
-    if (!initialized) {
+    if (!initialized)
         exit(0);
-    }
+    pthread_exit(0);
 }
 
 #ifdef USE_SEMAPHORES