diff --git a/homeassistant/components/timer/__init__.py b/homeassistant/components/timer/__init__.py
index 215aa8577f7..e5564736c74 100644
--- a/homeassistant/components/timer/__init__.py
+++ b/homeassistant/components/timer/__init__.py
@@ -388,5 +388,5 @@ class Timer(RestoreEntity):
         """Handle when the config is updated."""
         self._config = config
         self._duration = cv.time_period_str(config[CONF_DURATION])
-        self._restore = config[CONF_RESTORE]
+        self._restore = config.get(CONF_RESTORE, DEFAULT_RESTORE)
         self.async_write_ha_state()