diff --git a/core/lib/Drupal/Core/Extension/ThemeInstaller.php b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
index b3b391e..d141d82 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
@@ -61,6 +61,11 @@ class ThemeInstaller implements ThemeInstallerInterface {
    */
   protected $logger;
 
+  /**
+   * @var \Drupal\Core\Extension\ModuleInstallerInterface|NULL
+   */
+  protected $moduleInstaller;
+
 
   /**
    * Constructs a new ThemeInstaller.
@@ -87,7 +92,7 @@ class ThemeInstaller implements ThemeInstallerInterface {
    * @param \Drupal\Core\State\StateInterface $state
    *   The state store.
    */
-  public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryInterface $config_factory, ConfigInstallerInterface $config_installer, ModuleHandlerInterface $module_handler, ConfigManagerInterface $config_manager, AssetCollectionOptimizerInterface $css_collection_optimizer, RouteBuilderInterface $route_builder, LoggerInterface $logger, StateInterface $state) {
+  public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryInterface $config_factory, ConfigInstallerInterface $config_installer, ModuleHandlerInterface $module_handler, ConfigManagerInterface $config_manager, AssetCollectionOptimizerInterface $css_collection_optimizer, RouteBuilderInterface $route_builder, LoggerInterface $logger, StateInterface $state, ModuleInstallerInterface $module_installer = NULL) {
     $this->themeHandler = $theme_handler;
     $this->configFactory = $config_factory;
     $this->configInstaller = $config_installer;
@@ -97,6 +102,17 @@ public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryI
     $this->routeBuilder = $route_builder;
     $this->logger = $logger;
     $this->state = $state;
+    $this->moduleInstaller = $module_installer;
+  }
+
+  /**
+   * @return \Drupal\Core\Extension\ModuleInstallerInterface
+   */
+  protected function getModuleInstaller() {
+    if (!isset($this->moduleInstaller)) {
+      $this->moduleInstaller = \Drupal::service('module_installer');
+    }
+    return $this->moduleInstaller;
   }
 
   /**
@@ -123,6 +139,10 @@ public function install(array $theme_list, $install_dependencies = TRUE) {
       }
 
       while (list($theme) = each($theme_list)) {
+        $module_dependencies = isset($theme_data[$theme]->requires['modules']) ? $theme_data[$theme]->requires['modules'] : [];
+        $this->moduleInstaller->install($module_dependencies);
+        unset($theme_data[$theme]->requires['modules']);
+
         // Add dependencies to the list. The new themes will be processed as
         // the while loop continues.
         foreach (array_keys($theme_data[$theme]->requires) as $dependency) {