diff --git a/core/modules/aggregator/aggregator.admin.inc b/core/modules/aggregator/aggregator.admin.inc
index 0ee5ee61f197171cd6a309751e594b87b4094a6b..7bb4c049317728f9892d4b683a138009ef6c6e92 100644
--- a/core/modules/aggregator/aggregator.admin.inc
+++ b/core/modules/aggregator/aggregator.admin.inc
@@ -435,7 +435,7 @@ function aggregator_admin_form($form, $form_state) {
     '#title' => t('Allowed HTML tags'),
     '#size' => 80,
     '#maxlength' => 255,
-    '#default_value' => variable_get('aggregator_allowed_html_tags', '<a> <b> <br> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>'),
+    '#default_value' => config('aggregator.settings')->get('items.allowed_html'),
     '#description' => t('A space-separated list of HTML tags allowed in the content of feed items. Disallowed tags are stripped from the content.'),
   );
 
@@ -484,7 +484,7 @@ function aggregator_admin_form($form, $form_state) {
       '#title' => t('Fetcher'),
       '#description' => t('Fetchers download data from an external source. Choose a fetcher suitable for the external source you would like to download from.'),
       '#options' => $fetchers,
-      '#default_value' => variable_get('aggregator_fetcher', 'aggregator'),
+      '#default_value' => config('aggregator.settings')->get('fetcher'),
     );
   }
   if (count($parsers) > 1) {
@@ -493,7 +493,7 @@ function aggregator_admin_form($form, $form_state) {
       '#title' => t('Parser'),
       '#description' => t('Parsers transform downloaded data into standard structures. Choose a parser suitable for the type of feeds you would like to aggregate.'),
       '#options' => $parsers,
-      '#default_value' => variable_get('aggregator_parser', 'aggregator'),
+      '#default_value' => config('aggregator.settings')->get('parser'),
     );
   }
   if (count($processors) > 1) {
@@ -502,7 +502,7 @@ function aggregator_admin_form($form, $form_state) {
       '#title' => t('Processors'),
       '#description' => t('Processors act on parsed feed data, for example they store feed items. Choose the processors suitable for your task.'),
       '#options' => $processors,
-      '#default_value' => variable_get('aggregator_processors', array('aggregator')),
+      '#default_value' => config('aggregator.settings')->get('processors'),
     );
   }
   if (count($basic_conf)) {
@@ -519,23 +519,31 @@ function aggregator_admin_form($form, $form_state) {
   // Implementing modules will expect an array at $form['modules'].
   $form['modules'] = array();
 
-  $form['actions'] = array('#type' => 'actions');
-  $form['actions']['submit'] = array(
-    '#type' => 'submit',
-    '#value' => t('Save configuration'),
-  );
-
-  return $form;
+  return system_config_form($form, $form_state);
 }
 
 /**
  * Form submission handler for aggregator_admin_form().
  */
 function aggregator_admin_form_submit($form, &$form_state) {
+  $config = config('aggregator.settings');
+  $config
+    ->set('items.allowed_html', $form_state['values']['aggregator_allowed_html_tags'])
+    ->set('items.expire', $form_state['values']['aggregator_clear'])
+    ->set('items.teaser_length', $form_state['values']['aggregator_teaser_length'])
+    ->set('source.list_max', $form_state['values']['aggregator_summary_items'])
+    ->set('source.category_selector', $form_state['values']['aggregator_category_selector']);
+
+  if (isset($form_state['values']['aggregator_fetcher'])) {
+    $config->set('fetcher', $form_state['values']['aggregator_fetcher']);
+  }
+  if (isset($form_state['values']['aggregator_parser'])) {
+    $config->set('parser', $form_state['values']['aggregator_parser']);
+  }
   if (isset($form_state['values']['aggregator_processors'])) {
-    $form_state['values']['aggregator_processors'] = array_filter($form_state['values']['aggregator_processors']);
+    $config->set('processors', array_filter($form_state['values']['aggregator_processors']));
   }
-  system_settings_form_submit($form, $form_state);
+  $config->save();
 }
 
 /**
diff --git a/core/modules/aggregator/aggregator.install b/core/modules/aggregator/aggregator.install
index ac4fce8befb0c53d74779a35ec7c75f1c985b455..bc0a3694f398fe4b079e46c8386305472733a5d5 100644
--- a/core/modules/aggregator/aggregator.install
+++ b/core/modules/aggregator/aggregator.install
@@ -5,20 +5,6 @@
  * Install, update and uninstall functions for the aggregator module.
  */
 
-/**
- * Implements hook_uninstall().
- */
-function aggregator_uninstall() {
-  variable_del('aggregator_allowed_html_tags');
-  variable_del('aggregator_summary_items');
-  variable_del('aggregator_clear');
-  variable_del('aggregator_category_selector');
-  variable_del('aggregator_fetcher');
-  variable_del('aggregator_parser');
-  variable_del('aggregator_processors');
-  variable_del('aggregator_teaser_length');
-}
-
 /**
  * Implements hook_schema().
  */
@@ -271,3 +257,21 @@ function aggregator_schema() {
 
   return $schema;
 }
+
+/**
+ * Moves aggregator settings from variables to config.
+ *
+ * @ingroup config_upgrade
+ */
+function aggregrator_update_8000() {
+  update_variables_to_config('aggregator.settings', array(
+    'aggregator_fetcher' => 'fetcher',
+    'aggregator_parser' => 'parser',
+    'aggregator_processors' => 'processors',
+    'aggregator_allowed_html_tags' => 'items.allowed_html',
+    'aggregator_teaser_length' => 'items.teaser_length',
+    'aggregator_clear' => 'items.expire',
+    'aggregator_summary_items' => 'source.list_max',
+    'aggregator_category_selector' => 'source.category_selector',
+  ));
+}
diff --git a/core/modules/aggregator/aggregator.module b/core/modules/aggregator/aggregator.module
index 2d37b73de9bde235ed6cc71c3662b27e7aad817a..e74cbb140b8a61c3b0845467f6547df302db08cf 100644
--- a/core/modules/aggregator/aggregator.module
+++ b/core/modules/aggregator/aggregator.module
@@ -596,14 +596,15 @@ function aggregator_remove($feed) {
  *   An array containing the fetcher, parser, and processors.
  */
 function _aggregator_get_variables() {
-  $fetcher = variable_get('aggregator_fetcher', 'aggregator');
+  $config = config('aggregator.settings');
+  $fetcher = $config->get('fetcher');
 
-  $parser = variable_get('aggregator_parser', 'aggregator');
+  $parser = $config->get('parser');
   if ($parser == 'aggregator') {
     include_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'aggregator') . '/aggregator.parser.inc';
   }
 
-  $processors = variable_get('aggregator_processors', array('aggregator'));
+  $processors = $config->get('processors');
   if (in_array('aggregator', $processors)) {
     include_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'aggregator') . '/aggregator.processor.inc';
   }
@@ -747,7 +748,7 @@ function theme_aggregator_block_item($variables) {
  *   The filtered content.
  */
 function aggregator_filter_xss($value) {
-  return filter_xss($value, preg_split('/\s+|<|>/', variable_get('aggregator_allowed_html_tags', '<a> <b> <br> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>'), -1, PREG_SPLIT_NO_EMPTY));
+  return filter_xss($value, preg_split('/\s+|<|>/', config('aggregator.settings')->get('items.allowed_html'), -1, PREG_SPLIT_NO_EMPTY));
 }
 
 /**
@@ -775,9 +776,12 @@ function aggregator_sanitize_configuration() {
     }
   }
   if ($reset) {
-    variable_del('aggregator_fetcher');
-    variable_del('aggregator_parser');
-    variable_del('aggregator_processors');
+    // Reset aggregator config if necessary using the module defaults.
+    config('aggregator.settings')
+      ->set('fetcher', 'aggregator')
+      ->set('parser', 'aggregator')
+      ->set('processors', array('aggregator' => 'aggregator'))
+      ->save();
     return TRUE;
   }
   return FALSE;
diff --git a/core/modules/aggregator/aggregator.pages.inc b/core/modules/aggregator/aggregator.pages.inc
index e41058728c02f84e09e7810376adbd9d7615965b..15b463312aa1473ede8b6926f8a805fbdbf51b7b 100644
--- a/core/modules/aggregator/aggregator.pages.inc
+++ b/core/modules/aggregator/aggregator.pages.inc
@@ -219,7 +219,7 @@ function aggregator_categorize_items($items, $feed_source = '') {
     }
     $done = TRUE;
     $form['categories'][$item->iid] = array(
-      '#type' => variable_get('aggregator_category_selector', 'checkboxes'),
+      '#type' => config('aggregator.settings')->get('source.category_selector'),
       '#default_value' => $selected,
       '#options' => $categories,
       '#size' => 10,
@@ -356,8 +356,9 @@ function aggregator_page_sources() {
   foreach ($result as $feed) {
     // Most recent items:
     $summary_items = array();
-    if (variable_get('aggregator_summary_items', 3)) {
-      $items = db_query_range('SELECT i.title, i.timestamp, i.link FROM {aggregator_item} i WHERE i.fid = :fid ORDER BY i.timestamp DESC', 0, variable_get('aggregator_summary_items', 3), array(':fid' => $feed->fid));
+    $aggregator_summary_items = config('aggregator.settings')->get('source.list_max');
+    if ($aggregator_summary_items) {
+      $items = db_query_range('SELECT i.title, i.timestamp, i.link FROM {aggregator_item} i WHERE i.fid = :fid ORDER BY i.timestamp DESC', 0, $aggregator_summary_items, array(':fid' => $feed->fid));
       foreach ($items as $item) {
         $summary_items[] = theme('aggregator_summary_item', array('item' => $item));
       }
@@ -380,9 +381,10 @@ function aggregator_page_categories() {
 
   $output = '';
   foreach ($result as $category) {
-    if (variable_get('aggregator_summary_items', 3)) {
+    $aggregator_summary_items = config('aggregator.settings')->get('source.list_max');
+    if ($aggregator_summary_items) {
       $summary_items = array();
-      $items = db_query_range('SELECT i.title, i.timestamp, i.link, f.title as feed_title, f.link as feed_link FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON i.iid = ci.iid LEFT JOIN {aggregator_feed} f ON i.fid = f.fid WHERE ci.cid = :cid ORDER BY i.timestamp DESC', 0, variable_get('aggregator_summary_items', 3), array(':cid' => $category->cid));
+      $items = db_query_range('SELECT i.title, i.timestamp, i.link, f.title as feed_title, f.link as feed_link FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON i.iid = ci.iid LEFT JOIN {aggregator_feed} f ON i.fid = f.fid WHERE ci.cid = :cid ORDER BY i.timestamp DESC', 0, $aggregator_summary_items, array(':cid' => $category->cid));
       foreach ($items as $item) {
         $summary_items[] = theme('aggregator_summary_item', array('item' => $item));
       }
@@ -439,7 +441,7 @@ function theme_aggregator_page_rss($variables) {
   foreach ($feeds as $feed) {
     switch ($feed_length) {
       case 'teaser':
-        $summary = text_summary($feed->description, NULL, variable_get('aggregator_teaser_length', 600));
+        $summary = text_summary($feed->description, NULL, config('aggregator.settings')->get('items.teaser_length'));
         if ($summary != $feed->description) {
           $summary .= '<p><a href="' . check_url($feed->link) . '">' . t('read more') . "</a></p>\n";
         }
diff --git a/core/modules/aggregator/aggregator.processor.inc b/core/modules/aggregator/aggregator.processor.inc
index 7fa86a9ad83ee239b9dabfb32822cc0d1c102ceb..c12c90fca6b2c4a3d2b80d87f05344037e67c689 100644
--- a/core/modules/aggregator/aggregator.processor.inc
+++ b/core/modules/aggregator/aggregator.processor.inc
@@ -70,7 +70,9 @@ function aggregator_aggregator_remove($feed) {
  * separate from aggregator API functionality.
  */
 function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
-  if (in_array('aggregator', variable_get('aggregator_processors', array('aggregator')))) {
+  $config = config('aggregator.settings');
+  $aggregator_processors = $config->get('processors');
+  if (in_array('aggregator', $aggregator_processors)) {
     $info = module_invoke('aggregator', 'aggregator_process', 'info');
     $items = drupal_map_assoc(array(3, 5, 10, 15, 20, 25), '_aggregator_items');
     $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200, 4838400, 9676800), 'format_interval');
@@ -83,7 +85,7 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
         '#title' => t('Default processor settings'),
         '#description' => $info['description'],
         '#collapsible' => TRUE,
-        '#collapsed' => !in_array('aggregator', variable_get('aggregator_processors', array('aggregator'))),
+        '#collapsed' => !in_array('aggregator', $aggregator_processors),
       );
     }
     else {
@@ -93,7 +95,7 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
     $form['modules']['aggregator']['aggregator_summary_items'] = array(
       '#type' => 'select',
       '#title' => t('Number of items shown in listing pages'),
-      '#default_value' => variable_get('aggregator_summary_items', 3),
+      '#default_value' => config('aggregator.settings')->get('source.list_max'),
       '#empty_value' => 0,
       '#options' => $items,
     );
@@ -101,7 +103,7 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
     $form['modules']['aggregator']['aggregator_clear'] = array(
       '#type' => 'select',
       '#title' => t('Discard items older than'),
-      '#default_value' => variable_get('aggregator_clear', 9676800),
+      '#default_value' => config('aggregator.settings')->get('items.expire'),
       '#options' => $period,
       '#description' => t('Requires a correctly configured <a href="@cron">cron maintenance task</a>.', array('@cron' => url('admin/reports/status'))),
     );
@@ -109,7 +111,7 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
     $form['modules']['aggregator']['aggregator_category_selector'] = array(
       '#type' => 'radios',
       '#title' => t('Select categories using'),
-      '#default_value' => variable_get('aggregator_category_selector', 'checkboxes'),
+      '#default_value' => config('aggregator.settings')->get('source.category_selector'),
       '#options' => array('checkboxes' => t('checkboxes'),
       'select' => t('multiple selector')),
       '#description' => t('For a small number of categories, checkboxes are easier to use, while a multiple selector works well with large numbers of categories.'),
@@ -117,7 +119,7 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
     $form['modules']['aggregator']['aggregator_teaser_length'] = array(
       '#type' => 'select',
       '#title' => t('Length of trimmed description'),
-      '#default_value' => variable_get('aggregator_teaser_length', 600),
+      '#default_value' => config('aggregator.settings')->get('items.teaser_length'),
       '#options' => drupal_map_assoc(array(0, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000), '_aggregator_characters'),
       '#description' => t("The maximum number of characters used in the trimmed version of content.")
     );
@@ -184,7 +186,7 @@ function aggregator_save_item($edit) {
  *   Object describing feed.
  */
 function aggregator_expire($feed) {
-  $aggregator_clear = variable_get('aggregator_clear', 9676800);
+  $aggregator_clear = config('aggregator.settings')->get('items.expire');
 
   if ($aggregator_clear != AGGREGATOR_CLEAR_NEVER) {
     // Remove all items that are older than flush item timer.
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
index 97f4392b456fd84b58699a5efc39b1a6fe09d016..536eec48ff3f6c812c6e6b15072b0850710d588c 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
@@ -24,7 +24,7 @@ function setUp() {
     // Do not remove old aggregator items during these tests, since our sample
     // feeds have hardcoded dates in them (which may be expired when this test
     // is run).
-    variable_set('aggregator_clear', AGGREGATOR_CLEAR_NEVER);
+    config('aggregator.settings')->set('items.expire', AGGREGATOR_CLEAR_NEVER)->save();
   }
 
   /**