diff --git a/py/modsys.c b/py/modsys.c
index 1411c964dd..10efd6004d 100644
--- a/py/modsys.c
+++ b/py/modsys.c
@@ -28,6 +28,11 @@ STATIC const mp_map_elem_t mp_module_sys_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_path), (mp_obj_t)&mp_sys_path_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_argv), (mp_obj_t)&mp_sys_argv_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_version_info), (mp_obj_t)&mp_sys_version_info_obj },
+#if MP_ENDIANNESS_LITTLE
+    { MP_OBJ_NEW_QSTR(MP_QSTR_byteorder), MP_OBJ_NEW_QSTR(MP_QSTR_little) },
+#else
+    { MP_OBJ_NEW_QSTR(MP_QSTR_byteorder), MP_OBJ_NEW_QSTR(MP_QSTR_big) },
+#endif
 
 #if MICROPY_MOD_SYS_STDFILES
     { MP_OBJ_NEW_QSTR(MP_QSTR_stdin), (mp_obj_t)&mp_sys_stdin_obj },
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index ad44f84fe9..a08af5a5ed 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -273,6 +273,9 @@ Q(utf-8)
 
 #if MICROPY_ENABLE_MOD_SYS
 Q(argv)
+Q(byteorder)
+Q(big)
+Q(little)
 Q(stdin)
 Q(stdout)
 Q(stderr)