diff --git a/setup.py b/setup.py
index 309dc52..6dfa3db 100644
--- a/setup.py
+++ b/setup.py
@@ -34,8 +34,8 @@
         libdir, 'lightdm_gtk_greeter_settings/installation_config.py')
     try:
         f = open(filename, 'w')
-        f.write('__all__ = [%s]\n' % ', '.join('"%s"' % k for k in values))
-        for k, v in values.items():
+        f.write('__all__ = [%s]\n' % ', '.join('"%s"' % k for k in sorted(values)))
+        for k, v in sorted(values.items()):
             f.write('%s = %s\n' % (k, v))
     except OSError as e:
         print("ERROR: Can't write installation config: %s" % e)