diff --git a/core/lib/Drupal/Core/Extension/ThemeInstaller.php b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
index d141d82..e93777b 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
@@ -139,9 +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']);
+        $module_dependencies = array_diff_key($theme_data[$theme]->requires, $theme_data);
+        $theme_dependencies = array_diff_key($theme_data[$theme]->requires, $module_dependencies);
+        $this->getModuleInstaller()->install(array_keys($module_dependencies));
+        $theme_data[$theme]->requires = $theme_dependencies;
 
         // Add dependencies to the list. The new themes will be processed as
         // the while loop continues.
diff --git a/core/modules/system/src/Tests/Extension/ThemeInstallerTest.php b/core/modules/system/src/Tests/Extension/ThemeInstallerTest.php
index 6fe81f7..8451ee4 100644
--- a/core/modules/system/src/Tests/Extension/ThemeInstallerTest.php
+++ b/core/modules/system/src/Tests/Extension/ThemeInstallerTest.php
@@ -9,7 +9,8 @@
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\Extension\ExtensionNameLengthException;
-use Drupal\simpletest\KernelTestBase;
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\test_theme_dependency\Service;
 
 /**
  * Tests installing and uninstalling of themes.
@@ -25,14 +26,16 @@ class ThemeInstallerTest extends KernelTestBase {
    */
   public static $modules = array('system');
 
-  public function containerBuild(ContainerBuilder $container) {
-    parent::containerBuild($container);
+  public function register(ContainerBuilder $container) {
+    parent::register($container);
+
     // Some test methods involve ModuleHandler operations, which attempt to
     // rebuild and dump routes.
     $container
       ->register('router.dumper', 'Drupal\Core\Routing\NullMatcherDumper');
   }
 
+
   protected function setUp() {
     parent::setUp();
     $this->installConfig(array('system'));
@@ -352,6 +355,15 @@ function testThemeInfoAlter() {
     $this->assertFalse(isset($system_list[$name]->info['regions']['test_region']));
   }
 
+  public function testThemeWithModuleDependency() {
+    $this->assertFalse($this->moduleHandler()->moduleExists('test_theme_dependency'));
+    $this->themeInstaller()->install(['test_theme_module_dependency']);
+    $this->assertTrue($this->moduleHandler()->moduleExists('test_theme_dependency'));
+
+    $service = \Drupal::service('test_theme_dependency.service');
+    $this->assertInstanceOf(Service::class, $service);
+  }
+
   /**
    * Returns the theme handler service.
    *
diff --git a/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/src/Service.php b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/src/Service.php
new file mode 100644
index 0000000..6313712
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/src/Service.php
@@ -0,0 +1,12 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\test_theme_dependency\Service.
+ */
+
+namespace Drupal\test_theme_dependency;
+
+class Service {
+
+}
diff --git a/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.info.yml b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.info.yml
new file mode 100644
index 0000000..74b1f7a
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.info.yml
@@ -0,0 +1,3 @@
+name: test theme dependency
+type: module
+core: 8.x
diff --git a/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.services.yml b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.services.yml
new file mode 100644
index 0000000..577b513
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_dependency/test_theme_dependency.services.yml
@@ -0,0 +1,3 @@
+services:
+  test_theme_dependency.service:
+    class: Drupal\test_theme_dependency\Service
diff --git a/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_module_dependency.info.yml b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_module_dependency.info.yml
new file mode 100644
index 0000000..3641cbf
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_module_dependency/test_theme_module_dependency.info.yml
@@ -0,0 +1,5 @@
+name: test theme with dependency
+type: theme
+core: 8.x
+dependencies:
+  - test_theme_dependency