diff -r f2ce9603346c Lib/test/test_sys.py
--- a/Lib/test/test_sys.py	Wed Oct 22 12:33:23 2014 +0200
+++ b/Lib/test/test_sys.py	Wed Oct 22 14:29:45 2014 +0200
@@ -744,6 +744,26 @@ class SysModuleTest(unittest.TestCase):
         c = sys.getallocatedblocks()
         self.assertIn(c, range(b - 50, b + 50))
 
+    @test.support.cpython_only
+    def test_is_finalizing(self):
+        # Don't use the atexit module because _Py_Finalizing is only set
+        # after calling atexit callbacks
+        code = textwrap.dedent('''
+            import sys
+
+            class AtExit:
+                is_finalizing = sys._is_finalizing
+
+                def __del__(self):
+                    print(self.is_finalizing(), flush=True)
+
+            # Keep a reference in the module namespace, so the AtExit
+            # destructor will be called at Python exit
+            ref = AtExit()
+        ''')
+        rc, stdout, stderr = assert_python_ok('-c', code)
+        self.assertEqual(stdout.rstrip(), b'True')
+
 
 @test.support.cpython_only
 class SizeofTest(unittest.TestCase):
diff -r f2ce9603346c Python/sysmodule.c
--- a/Python/sysmodule.c	Wed Oct 22 12:33:23 2014 +0200
+++ b/Python/sysmodule.c	Wed Oct 22 14:29:45 2014 +0200
@@ -1116,6 +1116,16 @@ PyDoc_STRVAR(sys_clear_type_cache__doc__
 "_clear_type_cache() -> None\n\
 Clear the internal type lookup cache.");
 
+static PyObject *
+sys_is_finalizing(PyObject* self, PyObject* args)
+{
+    return PyBool_FromLong(_Py_Finalizing != NULL);
+}
+
+PyDoc_STRVAR(is_finalizing_doc,
+"_is_finalizing()\n\
+Return True is Python is exiting.");
+
 
 static PyMethodDef sys_methods[] = {
     /* Might as well keep this in alphabetic order */
@@ -1191,6 +1201,8 @@ static PyMethodDef sys_methods[] = {
     {"call_tracing", sys_call_tracing, METH_VARARGS, call_tracing_doc},
     {"_debugmallocstats", sys_debugmallocstats, METH_NOARGS,
      debugmallocstats_doc},
+    {"_is_finalizing", sys_is_finalizing, METH_NOARGS,
+     is_finalizing_doc},
     {NULL,              NULL}           /* sentinel */
 };