diff --git a/core/includes/form.inc b/core/includes/form.inc
index 87f8edf..502aec9 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -2575,22 +2575,23 @@ function theme_form($variables) {
 }
 
 /**
- * Returns HTML for a textarea form element.
+ * Prepares variables for textarea templates.
  *
- * @param $variables
+ * Default template: textarea.html.twig.
+ *
+ * @param array $variables
  *   An associative array containing:
  *   - element: An associative array containing the properties of the element.
  *     Properties used: #title, #value, #description, #rows, #cols,
  *     #placeholder, #required, #attributes, #resizable
  *
- * @ingroup themeable
  */
-function theme_textarea($variables) {
+function template_preprocess_textarea(&$variables) {
   $element = $variables['element'];
   element_set_attributes($element, array('id', 'name', 'rows', 'cols', 'placeholder'));
-  _form_set_attributes($element, array('form-textarea'));
+  $variables['attributes'] = $element['#attributes'];
 
-  $wrapper_attributes = array(
+  $variables['wrapper_attributes'] = array(
     'class' => array('form-textarea-wrapper'),
   );
 
@@ -2599,10 +2600,11 @@ function theme_textarea($variables) {
     $element['#attributes']['class'][] = 'resize-' . $element['#resizable'];
   }
 
-  $output = '<div' . new Attribute($wrapper_attributes) . '>';
-  $output .= '<textarea' . new Attribute($element['#attributes']) . '>' . String::checkPlain($element['#value']) . '</textarea>';
-  $output .= '</div>';
-  return $output;
+  $variables['attributes']['class'] = array();
+  $variables['attributes']['class'][] = 'form-textarea';
+  $variables['attributes']['class'] = array_merge($variables['attributes']['class'], $element['#attributes']['class']);
+
+  $variables['value'] = String::checkPlain($element['#value']);
 }
 
 /**
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 37f04f9..43111fb 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2701,6 +2701,7 @@ function drupal_common_theme() {
     ),
     'textarea' => array(
       'render element' => 'element',
+      'template' => 'textarea',
     ),
     'tableselect' => array(
       'render element' => 'element',
diff --git a/core/modules/system/templates/textarea.html.twig b/core/modules/system/templates/textarea.html.twig
new file mode 100644
index 0000000..4955f7c
--- /dev/null
+++ b/core/modules/system/templates/textarea.html.twig
@@ -0,0 +1,18 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a 'textarea' #type form element.
+ *
+ * Available variables
+ * - wrapper_attributes: A list of HTML attributes for the wrapper element.
+ * - attributes: A list of HTML attributes for the textarea element.
+ * - value: The textarea content.
+ *
+ * @see template_preprocess_textarea()
+ *
+ * @ingroup themeable
+ */
+ @todo: remove this file once http://drupal.org/node/1819284 is resolved.
+ This is identical to core/modules/system/templates/container.html.twig
+#}
+<div{{ wrapper_attributes }}><textarea{{ attributes }}>{{ value }}</textarea></div>