diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index a83b7a5..0c02e35 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -624,6 +624,8 @@ function theme($hook, $variables = array()) {
   }
   // Allow suggestions to be altered via hook_theme_suggestions_HOOK_alter().
   Drupal::moduleHandler()->alter('theme_suggestions_' . $base_theme_hook, $suggestions, $variables);
+  // Allow suggestions to be altered via hook_theme_suggestions_alter().
+  Drupal::moduleHandler()->alter('theme_suggestions', $suggestions, $variables, $base_theme_hook);
 
   // Check if each suggestion exists in the theme registry, and if so,
   // use it instead of the hook that theme() was called with. For example, a