diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index f7c647c..9b804e6 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -333,7 +333,8 @@
     # load the installed pyconfig.h:
     config_h = get_config_h_filename()
     try:
-        parse_config_h(open(config_h), vars)
+        with open(config_h) as f:
+            parse_config_h(f, vars)
     except IOError as e:
         msg = "invalid Python installation: unable to open %s" % config_h
         if hasattr(e, "strerror"):