diff -u b/core/modules/taxonomy/lib/Drupal/taxonomy/Form/TermDeleteForm.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Form/TermDeleteForm.php
--- b/core/modules/taxonomy/lib/Drupal/taxonomy/Form/TermDeleteForm.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Form/TermDeleteForm.php
@@ -90,7 +90,7 @@
     $vocabulary = $this->vocabularyStorageController->load($this->entity->bundle());
 
     // @todo Move to storage controller http://drupal.org/node/1988712
-    taxonomy_check_vocabulary_hierarchy(reset($vocabulary), array('tid' => $this->entity->id()));
+    taxonomy_check_vocabulary_hierarchy($vocabulary, array('tid' => $this->entity->id()));
 
     drupal_set_message(t('Deleted term %name.', array('%name' => $this->entity->label())));
     watchdog('taxonomy', 'Deleted term %name.', array('%name' => $this->entity->label()), WATCHDOG_NOTICE);