diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index 024f3ed..590b3c4 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -1659,3 +1659,35 @@ function taxonomy_taxonomy_term_delete(TaxonomyTerm $term) {
 /**
  * @} End of "defgroup taxonomy_index"
  */
+
+/**
+ * Implements hook_entity_query_alter().
+ *
+ * Converts EntityFieldQuery instances on taxonomy terms that have an entity
+ * condition on term bundles (vocabulary machine names). Since the vocabulary
+ * machine name is not present in the {taxonomy_term_data} table itself, we have
+ * to convert the bundle condition into a proprety condition of vocabulary IDs
+ * to match against {taxonomy_term_data}.vid.
+ */
+function taxonomy_entity_query_alter($query) {
+  $conditions = &$query->entityConditions;
+
+  // Alter only taxonomy term queries with bundle conditions.
+  if (isset($conditions['entity_type']) && $conditions['entity_type']['value'] == 'taxonomy_term' && isset($conditions['bundle'])) {
+    // Convert vocabulary machine names to vocabulary IDs.
+    $vocabulary_data = taxonomy_vocabulary_get_names();
+    $vids = array();
+    if (is_array($conditions['bundle']['value'])) {
+      foreach ($conditions['bundle']['value'] as $vocabulary_machine_name) {
+        $vids[] = $vocabulary_data[$vocabulary_machine_name]->vid;
+      }
+    }
+    else {
+      $vocabulary_machine_name = $conditions['bundle']['value'];
+      $vids = $vocabulary_data[$vocabulary_machine_name]->vid;
+    }
+
+    $query->propertyCondition('vid', $vids, $conditions['bundle']['operator']);
+    unset($conditions['bundle']);
+  }
+}
diff --git a/core/modules/taxonomy/taxonomy.test b/core/modules/taxonomy/taxonomy.test
index a26d15f..a4daba7 100644
--- a/core/modules/taxonomy/taxonomy.test
+++ b/core/modules/taxonomy/taxonomy.test
@@ -1948,5 +1948,22 @@ class TaxonomyEFQTestCase extends TaxonomyWebTestCase {
     $result = $result['taxonomy_term'];
     asort($result);
     $this->assertEqual(array_keys($terms), array_keys($result), 'Taxonomy terms were retrieved by EntityFieldQuery.');
+
+    // Create a second vocabulary and five more terms.
+    $vocabulary2 = $this->createVocabulary();
+    $terms2 = array();
+    for ($i = 0; $i < 5; $i++) {
+      $term = $this->createTerm($vocabulary2);
+      $terms2[$term->tid] = $term;
+    }
+
+    $query = new EntityFieldQuery();
+    $query->entityCondition('entity_type', 'taxonomy_term');
+    $query->entityCondition('bundle', $vocabulary2->machine_name);
+    $result = $query->execute();
+    $result = $result['taxonomy_term'];
+    asort($result);
+    $this->assertEqual(array_keys($terms2), array_keys($result), format_string('Taxonomy terms from the %name vocabulary were retrieved by EntityFieldQuery.', array('%name' => $vocabulary2->name)));
   }
+
 }