diff -u b/core/includes/theme.inc b/core/includes/theme.inc
--- b/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -568,7 +568,7 @@
     $context = array(
       'hook' => $hook,
       'suggestions' => $suggestions,
-      'suggestion' => $suggestion,
+      'suggestion' => isset($suggestion) ? $suggestion : NULL,
       'info' => $info,
     );
     foreach ($info['preprocess functions'] as $preprocessor_function) {
@@ -618,7 +618,7 @@
       $context = array(
         'hook' => $hook,
         'suggestions' => $suggestions,
-        'suggestion' => $suggestion,
+        'suggestion' => isset($suggestion) ? $suggestion : NULL,
         'info' => $info,
       );
       template_preprocess($default_template_variables, $context);
@@ -2524,6 +2524,16 @@
       'render element' => 'page',
       'template' => 'page',
     ),
+    'page__maintenance' => array(
+      'base hook' => 'page',
+      'render element' => 'page',
+      'template' => 'page--maintenance',
+    ),
+    'page__maintenance__install' => array(
+      'base hook' => 'page',
+      'render element' => 'page',
+      'template' => 'page--maintenance--install',
+    ),
     'region' => array(
       'render element' => 'elements',
       'template' => 'region',