diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 3af30c8..b909eb9 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -322,7 +322,9 @@ function theme_admin_block($variables) {
 }
 
 /**
- * Returns HTML for the content of an administrative block.
+ * Prepares variables for administrative content block template.
+ *
+ * Default template: admin-block-content.html.twig.
  *
  * @param $variables
  *   An associative array containing:
@@ -333,25 +335,23 @@ function theme_admin_block($variables) {
  *
  * @ingroup themeable
  */
-function theme_admin_block_content($variables) {
-  $content = $variables['content'];
-  $output = '';
-
-  if (!empty($content)) {
-    $class = 'admin-list';
-    if ($compact = system_admin_compact_mode()) {
-      $class .= ' compact';
+function template_preprocess_admin_block_content(&$variables) {
+  if (!empty($variables['content'])) {
+    $compact = system_admin_compact_mode();
+    $variables['attributes'] = array('class' => array('admin-list'));
+    if ($compact) {
+      $variables['attributes']['class'][] = 'compact';
     }
-    $output .= '<dl class="' . $class . '">';
-    foreach ($content as $item) {
-      $output .= '<dt>' . l($item['title'], $item['href'], $item['localized_options']) . '</dt>';
+    foreach ($variables['content'] as $key => $item) {
+      $variables['content'][$key]['link'] = l($item['title'], $item['href'], $item['localized_options']);
       if (!$compact && isset($item['description'])) {
-        $output .= '<dd>' . filter_xss_admin($item['description']) . '</dd>';
+        $variables['content'][$key]['description'] = filter_xss_admin($item['description']);
+      }
+      else {
+        $variables['content'][$key]['description'] = FALSE;
       }
     }
-    $output .= '</dl>';
   }
-  return $output;
 }
 
 /**
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index ee3466d..3ff8fb6 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -178,6 +178,7 @@ function system_theme() {
     'admin_block_content' => array(
       'variables' => array('content' => NULL),
       'file' => 'system.admin.inc',
+      'template' => 'admin-block-content',
     ),
     'system_admin_index' => array(
       'variables' => array('menu_items' => NULL),
diff --git a/core/modules/system/templates/admin-block-content.html.twig b/core/modules/system/templates/admin-block-content.html.twig
new file mode 100644
index 0000000..d3fbd5a
--- /dev/null
+++ b/core/modules/system/templates/admin-block-content.html.twig
@@ -0,0 +1,28 @@
+{#
+/**
+ * @file
+ * Default theme implementation for the content of an administrative block.
+ *
+ * Available variables:
+ * - content: A list containing information about the block. Each element
+ *   of the array represents an administrative menu item, and must at least
+ *   contain the keys 'title', 'href', and 'localized_options', which are
+ *   passed to l(). A 'description' key may also be provided.
+ * - attributes: HTML attributes to be aded to the element.
+ * - is_compact_mode: It defines if compact mode is used.
+ *
+ * @see template_preprocess_admin_block_content()
+ *
+ * @ingroup themeable
+ */
+#}
+{% if content %}
+  <dl{{ attributes }}>
+    {% for item in content %}
+      <dt>{{ item.link }}</dt>
+      {% if item.description %}
+        <dd>{{ item.description }}</dd>
+      {% endif %}
+    {% endfor %}
+  </dl>
+{% endif %}