diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/process/Explode.php b/core/modules/migrate_drupal/src/Plugin/migrate/process/Explode.php
new file mode 100644
index 0000000..8f91d3f
--- /dev/null
+++ b/core/modules/migrate_drupal/src/Plugin/migrate/process/Explode.php
@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\migrate_drupal\Plugin\migrate\process\Explode.
+ */
+
+namespace Drupal\migrate_drupal\Plugin\migrate\process;
+
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\MigrateException;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\Row;
+
+/**
+ * This plugin explodes a value.
+ *
+ * @MigrateProcessPlugin(
+ *   id = "explode"
+ * )
+ */
+class Explode extends ProcessPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    if (is_string($value[0])) {
+      if (!empty($this->configuration['delimiter'])) {
+        return explode($this->configuration['delimiter'], $value[0]);
+      }
+      else {
+        throw new MigrateException(sprintf('delimiter is empty', var_export($value, TRUE)));
+      }
+    }
+    else {
+      throw new MigrateException(sprintf('%s is not a string', var_export($value, TRUE)));
+    }
+  }
+
+}
diff --git a/core/modules/migrate_drupal/tests/fixtures/drupal7.php b/core/modules/migrate_drupal/tests/fixtures/drupal7.php
index 78651e4..833e469 100644
--- a/core/modules/migrate_drupal/tests/fixtures/drupal7.php
+++ b/core/modules/migrate_drupal/tests/fixtures/drupal7.php
@@ -41532,10 +41532,18 @@
   'value' => 'i:1024;',
 ))
 ->values(array(
+  'name' => 'theme_bartik_settings',
+  'value' => 'a:18:{s:11:"toggle_logo";i:1;s:11:"toggle_name";i:1;s:13:"toggle_slogan";i:1;s:24:"toggle_node_user_picture";i:1;s:27:"toggle_comment_user_picture";i:1;s:32:"toggle_comment_user_verification";i:1;s:14:"toggle_favicon";i:1;s:16:"toggle_main_menu";i:1;s:21:"toggle_secondary_menu";i:1;s:12:"default_logo";i:0;s:9:"logo_path";s:16:"public://gnu.png";s:15:"default_favicon";i:1;s:12:"favicon_path";s:0:"";s:14:"favicon_upload";s:0:"";s:6:"scheme";s:7:"default";s:7:"palette";a:9:{s:3:"top";s:7:"#0779bf";s:6:"bottom";s:7:"#48a9e4";s:2:"bg";s:7:"#ffffff";s:7:"sidebar";s:7:"#f6f6f2";s:14:"sidebarborders";s:7:"#f9f9f9";s:6:"footer";s:7:"#292929";s:11:"titleslogan";s:7:"#fffeff";s:4:"text";s:7:"#3b3b3b";s:4:"link";s:7:"#0071B3";}s:5:"theme";s:6:"bartik";s:4:"info";a:12:{s:6:"fields";a:9:{s:3:"top";s:10:"Header top";s:6:"bottom";s:13:"Header bottom";s:2:"bg";s:15:"Main background";s:7:"sidebar";s:18:"Sidebar background";s:14:"sidebarborders";s:15:"Sidebar borders";s:6:"footer";s:17:"Footer background";s:11:"titleslogan";s:16:"Title and slogan";s:4:"text";s:10:"Text color";s:4:"link";s:10:"Link color";}s:7:"schemes";a:6:{s:7:"default";a:2:{s:5:"title";s:21:"Blue Lagoon (default)";s:6:"colors";a:9:{s:3:"top";s:7:"#0779bf";s:6:"bottom";s:7:"#48a9e4";s:2:"bg";s:7:"#ffffff";s:7:"sidebar";s:7:"#f6f6f2";s:14:"sidebarborders";s:7:"#f9f9f9";s:6:"footer";s:7:"#292929";s:11:"titleslogan";s:7:"#fffeff";s:4:"text";s:7:"#3b3b3b";s:4:"link";s:7:"#0071B3";}}s:9:"firehouse";a:2:{s:5:"title";s:9:"Firehouse";s:6:"colors";a:9:{s:3:"top";s:7:"#cd2d2d";s:6:"bottom";s:7:"#cf3535";s:2:"bg";s:7:"#ffffff";s:7:"sidebar";s:7:"#f1f4f0";s:14:"sidebarborders";s:7:"#ededed";s:6:"footer";s:7:"#1f1d1c";s:11:"titleslogan";s:7:"#fffeff";s:4:"text";s:7:"#3b3b3b";s:4:"link";s:7:"#d6121f";}}s:3:"ice";a:2:{s:5:"title";s:3:"Ice";s:6:"colors";a:9:{s:3:"top";s:7:"#d0d0d0";s:6:"bottom";s:7:"#c2c4c5";s:2:"bg";s:7:"#ffffff";s:7:"sidebar";s:7:"#ffffff";s:14:"sidebarborders";s:7:"#cccccc";s:6:"footer";s:7:"#24272c";s:11:"titleslogan";s:7:"#000000";s:4:"text";s:7:"#4a4a4a";s:4:"link";s:7:"#019dbf";}}s:4:"plum";a:2:{s:5:"title";s:4:"Plum";s:6:"colors";a:9:{s:3:"top";s:7:"#4c1c58";s:6:"bottom";s:7:"#593662";s:2:"bg";s:7:"#fffdf7";s:7:"sidebar";s:7:"#edede7";s:14:"sidebarborders";s:7:"#e7e7e7";s:6:"footer";s:7:"#2c2c28";s:11:"titleslogan";s:7:"#ffffff";s:4:"text";s:7:"#301313";s:4:"link";s:7:"#9d408d";}}s:5:"slate";a:2:{s:5:"title";s:5:"Slate";s:6:"colors";a:9:{s:3:"top";s:7:"#4a4a4a";s:6:"bottom";s:7:"#4e4e4e";s:2:"bg";s:7:"#ffffff";s:7:"sidebar";s:7:"#ffffff";s:14:"sidebarborders";s:7:"#d0d0d0";s:6:"footer";s:7:"#161617";s:11:"titleslogan";s:7:"#ffffff";s:4:"text";s:7:"#3b3b3b";s:4:"link";s:7:"#0073b6";}}s:0:"";a:2:{s:5:"title";s:6:"Custom";s:6:"colors";a:0:{}}}s:3:"css";a:1:{i:0;s:14:"css/colors.css";}s:4:"copy";a:1:{i:0;s:8:"logo.png";}s:9:"gradients";a:1:{i:0;a:3:{s:9:"dimension";a:4:{i:0;i:0;i:1;i:0;i:2;i:0;i:3;i:0;}s:9:"direction";s:8:"vertical";s:6:"colors";a:2:{i:0;s:3:"top";i:1;s:6:"bottom";}}}s:4:"fill";a:0:{}s:6:"slices";a:0:{}s:12:"blend_target";s:7:"#ffffff";s:11:"preview_css";s:17:"color/preview.css";s:10:"preview_js";s:16:"color/preview.js";s:12:"preview_html";s:18:"color/preview.html";s:10:"base_image";s:14:"color/base.png";}}',
+))
+->values(array(
   'name' => 'theme_default',
   'value' => 's:6:"bartik";',
 ))
 ->values(array(
+  'name' => 'theme_seven_settings',
+  'value' => 'a:15:{s:11:"toggle_logo";i:1;s:11:"toggle_name";i:1;s:13:"toggle_slogan";i:1;s:24:"toggle_node_user_picture";i:1;s:27:"toggle_comment_user_picture";i:0;s:32:"toggle_comment_user_verification";i:1;s:14:"toggle_favicon";i:1;s:16:"toggle_main_menu";i:1;s:21:"toggle_secondary_menu";i:0;s:12:"default_logo";i:1;s:9:"logo_path";s:0:"";s:11:"logo_upload";s:0:"";s:15:"default_favicon";i:1;s:12:"favicon_path";s:0:"";s:14:"favicon_upload";s:0:"";}',
+))
+->values(array(
   'name' => 'tracker_batch_size',
   'value' => 'i:999;',
 ))
diff --git a/core/modules/migrate_drupal/tests/src/Unit/process/ExplodeTest.php b/core/modules/migrate_drupal/tests/src/Unit/process/ExplodeTest.php
new file mode 100644
index 0000000..31b5dfe
--- /dev/null
+++ b/core/modules/migrate_drupal/tests/src/Unit/process/ExplodeTest.php
@@ -0,0 +1,82 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\migrate_drupal\Unit\Plugin\migrate\process\ExplodeTest.
+ */
+
+namespace Drupal\Tests\migrate_drupal\Unit\Plugin\migrate\process;
+
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\migrate\Plugin\MigrateProcessInterface;
+use Drupal\migrate_drupal\Plugin\migrate\process\Explode;
+use Drupal\Tests\migrate\Unit\process\MigrateProcessTestCase;
+
+/**
+ * Tests the Explode process plugin.
+ *
+ * @group migrate_drupal
+ */
+class ExplodeTest extends MigrateProcessTestCase {
+
+  /**
+   * The module handler.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * The migration plugin.
+   *
+   * @var \Drupal\migrate\Plugin\MigrateProcessInterface
+   */
+  protected $migrationPlugin;
+
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->moduleHandler = $this->prophesize(ModuleHandlerInterface::class);
+    $this->migrationPlugin = $this->prophesize(MigrateProcessInterface::class);
+    parent::setUp();
+  }
+
+  /**
+   * Tests the transform process.
+   */
+  public function testTransform() {
+    $configuration['delimiter'] = '_';
+    $this->plugin = new Explode($configuration, 'explode', [], $this->moduleHandler->reveal(), $this->migrationPlugin->reveal());
+    $source = ['color_bartik_stylesheets'];
+    $result = ['color', 'bartik', 'stylesheets'];
+    $transformed_value = $this->plugin->transform($source, $this->migrateExecutable, $this->row, 'destinationproperty');
+    $this->assertSame($result, $transformed_value);
+  }
+
+  /**
+   * Tests invalid input.
+   *
+   * @expectedException \Drupal\migrate\MigrateException
+   * @expectedExceptionMessage is not a string
+   */
+  public function testSourceString() {
+    $configuration['delimiter'] = '_';
+    $this->plugin = new Explode($configuration, 'explode', [], $this->moduleHandler->reveal(), $this->migrationPlugin->reveal());
+    $this->plugin->transform([ ['color_bartik_stylesheets'] ], $this->migrateExecutable, $this->row, 'destinationproperty');
+  }
+
+  /**
+   * Tests empty delimter.
+   *
+   * @expectedException \Drupal\migrate\MigrateException
+   * @expectedExceptionMessage delimiter is empty
+   */
+  public function testDelimiterEmpty() {
+    $configuration['delimiter'] = '';
+    $this->plugin = new Explode($configuration, 'explode', [], $this->moduleHandler->reveal(), $this->migrationPlugin->reveal());
+    $this->plugin->transform(['color_bartik_stylesheets'], $this->migrateExecutable, $this->row, 'destinationproperty');
+  }
+
+}
diff --git a/core/modules/system/migration_templates/d7_theme_settings.yml b/core/modules/system/migration_templates/d7_theme_settings.yml
new file mode 100644
index 0000000..70e041e
--- /dev/null
+++ b/core/modules/system/migration_templates/d7_theme_settings.yml
@@ -0,0 +1,45 @@
+id: d7_theme_settings
+label: D7 theme settings
+migration_tags:
+  - Drupal 7
+source:
+  plugin: d7_theme_settings
+  constants:
+    config_suffix: '.settings'
+process:
+  # build the configuration name from the variable name, i.e.
+  # theme_bartik_settings becomes bartik.settings
+  configuration_name:
+    -
+      plugin: explode
+      source:
+        - name
+      delimiter: _
+    -
+      plugin: extract
+      index:
+        - 1
+    -
+      plugin: concat
+      source:
+        -
+        - constants/config_suffix
+  toggle_logo: theme_settings/toggle_logo
+  toggle_name: value/toggle_name
+  toggle_slogan: value/toggle_slogan
+  toggle_node_user_picture: value/toggle_node_user_picture
+  toggle_comment_user_picture: value/toggle_comment_user_picture
+  toggle_comment_user_verification: value/toggle_comment_user_verification
+  toggle_favicon: value/toggle_favicon
+  default_logo: value/default_logo
+  logo_path: value/logo_path
+  logo_upload: value/logo_upload
+  default_favicon: value/default_favicon
+  favicon_path: value/favicon_path
+  favicon_mimetype: value/favicon_mimetype
+# Ignore settings not present in Drupal 8
+#  value/favicon_upload
+#  value/toggle_main_menu
+#  value/toggle_secondary_menu
+destination:
+  plugin: d7_theme_settings
diff --git a/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php b/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php
new file mode 100644
index 0000000..32e7b45
--- /dev/null
+++ b/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php
@@ -0,0 +1,89 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Plugin\migrate\destination\d7\ThemeSettings.
+ *
+ * Provides ThemeSettings destination plugin.
+ */
+
+namespace Drupal\system\Plugin\migrate\destination\d7;
+
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\migrate\Entity\MigrationInterface;
+use Drupal\migrate\Row;
+use Drupal\migrate\Plugin\migrate\destination\DestinationBase;
+
+/**
+ * Persist color data to the config system.
+ *
+ * @MigrateDestination(
+ *   id = "d7_theme_settings"
+ * )
+ */
+class ThemeSettings extends DestinationBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The configuration factory.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $config_factory;
+
+  /**
+   * Constructs a BlockedIP object.
+   *
+   * @param array $configuration
+   *  Plugin configuration.
+   * @param string $plugin_id
+   *  The plugin ID.
+   * @param mixed $plugin_definition
+   *  The plugin definiiton.
+   * @param \Drupal\migrate\Entity\MigrationInterface $migration
+   *  The current migration.
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The configuration factory.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, ConfigFactoryInterface $config_factory) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
+    $this->config_factory = $config_factory;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
+    return new static(
+        $configuration, $plugin_id, $plugin_definition, $migration, $container->get('config.factory')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function import(Row $row, array $old_destination_id_values = array()) {
+    $configuration_name = $row->getDestinationProperty('configuration_name');
+    $config = $this->config_factory->getEditable($configuration_name);
+    $theme_settings = $row->getDestination();
+    unset($theme_settings['configuration_name']);
+    theme_settings_convert_to_config($theme_settings, $config);
+    $config->save();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds() {
+    $ids['name']['type'] = 'string';
+    return $ids;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(MigrationInterface $migration = NULL) {
+  }
+
+}
diff --git a/core/modules/system/src/Plugin/migrate/source/d7/ThemeSettings.php b/core/modules/system/src/Plugin/migrate/source/d7/ThemeSettings.php
new file mode 100644
index 0000000..0c25aa6
--- /dev/null
+++ b/core/modules/system/src/Plugin/migrate/source/d7/ThemeSettings.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Plugin\migrate\source\d7\ThemeSettings.
+ */
+
+namespace Drupal\system\Plugin\migrate\source\d7;
+
+use Drupal\migrate_drupal\Plugin\migrate\source\VariableMultiRow;
+
+/**
+ * Drupal 7 system source from database.
+ *
+ * @MigrateSource(
+ *   id = "d7_theme_settings",
+ *   source_provider = "system"
+ * )
+ */
+class ThemeSettings extends VariableMultiRow {
+  /**
+   * {@inheritdoc}
+   */
+  protected $variables;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query() {
+    return $this->select('variable', 'v')
+        ->fields('v', array('name', 'value'))
+        ->condition('name', 'theme_%_settings', 'LIKE');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields() {
+    return array(
+      'name' => $this->t('Theme settings variable for a theme.'),
+      'value' => $this->t('The value.'),
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds() {
+    $ids['name']['type'] = 'string';
+    return $ids;
+  }
+
+}
diff --git a/core/modules/system/src/Tests/Migrate/d7/MigrateThemeSettingsTest.php b/core/modules/system/src/Tests/Migrate/d7/MigrateThemeSettingsTest.php
new file mode 100644
index 0000000..6be8309
--- /dev/null
+++ b/core/modules/system/src/Tests/Migrate/d7/MigrateThemeSettingsTest.php
@@ -0,0 +1,79 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Migrate\d7\MigrateThemeSettingsTest.
+ */
+
+namespace Drupal\system\Tests\Migrate\d7;
+
+use Drupal\migrate_drupal\Tests\d7\MigrateDrupal7TestBase;
+
+/**
+ * Tests migration of Theme settings variables to configuration.
+ *
+ * @group system
+ */
+class MigrateThemeSettingsTest extends MigrateDrupal7TestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['system'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Set Bartik and Seven as the default public and admin theme.
+    $config = $this->config('system.theme');
+    $config->set('default', 'bartik');
+    $config->set('admin', 'seven');
+    $config->save();
+
+    // Install one of D8's test themes.
+    \Drupal::service('theme_handler')->install(['bartik']);
+    // Install one of D8's test themes.
+    \Drupal::service('theme_handler')->install(['seven']);
+    $this->executeMigration('d7_theme_settings');
+  }
+
+  /**
+   * Tests migration of system's variables to configuration.
+   */
+  public function testMigrateThemeSettings() {
+    $config = $this->config('bartik.settings');
+    $this->assertIdentical('', $config->get('favicon.path'));
+    $this->assertTrue($config->get('favicon.use_default'));
+
+    $this->assertTrue($config->get('features.comment_user_picture'));
+    $this->assertTrue($config->get('features.comment_user_verification'));
+    $this->assertTrue($config->get('features.favicon'));
+    $this->assertTrue($config->get('features.node_user_picture'));
+    $this->assertFalse($config->get('features.logo'));
+    $this->assertTrue($config->get('features.name'));
+    $this->assertTrue($config->get('features.slogan'));
+
+    $this->assertIdentical('public://gnu.png', $config->get('logo.path'));
+    $this->assertFalse($config->get('logo.use_default'));
+
+
+    $config = $this->config('seven.settings');
+    $this->assertIdentical('', $config->get('favicon.path'));
+    $this->assertTrue($config->get('favicon.use_default'));
+
+    $this->assertFalse($config->get('features.comment_user_picture'));
+    $this->assertTrue($config->get('features.comment_user_verification'));
+    $this->assertTrue($config->get('features.favicon'));
+    $this->assertTrue($config->get('features.node_user_picture'));
+    $this->assertFalse($config->get('features.logo'));
+    $this->assertTrue($config->get('features.name'));
+    $this->assertTrue($config->get('features.slogan'));
+
+    $this->assertIdentical('', $config->get('logo.path'));
+    $this->assertTrue($config->get('logo.use_default'));
+  }
+
+}
diff --git a/core/modules/system/tests/src/Unit/Plugin/migrate/source/d7/ThemeSettingsTest.php b/core/modules/system/tests/src/Unit/Plugin/migrate/source/d7/ThemeSettingsTest.php
new file mode 100644
index 0000000..5b81225
--- /dev/null
+++ b/core/modules/system/tests/src/Unit/Plugin/migrate/source/d7/ThemeSettingsTest.php
@@ -0,0 +1,61 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\system\Unit\Plugin\migrate\source\d7\ThemeSettingsTest.
+ */
+
+namespace Drupal\Tests\system\Unit\Plugin\migrate\source\d7;
+
+use Drupal\Tests\migrate\Unit\MigrateSqlSourceTestCase;
+
+/**
+ * Tests D7 system source plugin.
+ *
+ * @group system
+ */
+class ThemeSettingsTest extends MigrateSqlSourceTestCase {
+
+  const PLUGIN_CLASS = 'Drupal\system\Plugin\migrate\source\d7\ThemeSettings';
+
+  protected $migrationConfiguration = [
+    'id' => 'test',
+    'source' => [
+      'plugin' => 'd7_theme_settings',
+    ],
+  ];
+
+  protected $expectedResults = [
+    [
+      'name' => 'theme_bartik_settings',
+      'value' => [
+        'toggle_logo' => 1,
+        'toggle_name' => 1,
+        'toggle_slogan' => 1,
+        'toggle_node_user_picture' => 1,
+        'toggle_comment_user_picture' => 1,
+        'toggle_comment_user_verification' => 1,
+        'toggle_favicon' => 1,
+        'toggle_main_menu' => 1,
+        'toggle_secondary_menu' => 1,
+        'default_logo' => 1,
+        'logo_path' => ' ',
+        'logo_upload' => ' ',
+        'default_favicon' => 1,
+        'favicon_path' => ' ',
+        'favicon_upload' => ' ',
+        'scheme' => 'firehouse',
+      ]
+    ]
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->databaseContents['variable'] = $this->expectedResults;
+    $this->databaseContents['variable'][0]['value'] = serialize( $this->expectedResults[0]['value']);
+    parent::setUp();
+  }
+
+}