diff --git a/core/core.services.yml b/core/core.services.yml
index 93e57d0fb4..e6f968202a 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -547,6 +547,12 @@ services:
       - { name: module_install.uninstall_validator }
     arguments: ['@string_translation', '@extension.list.module']
     lazy: true
+  module_required_by_themes_uninstall_validator:
+    class: Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator
+    tags:
+      - { name: module_install.uninstall_validator }
+    arguments: ['@string_translation', '@extension.list.module', '@extension.list.theme']
+    lazy: true
   theme_handler:
     class: Drupal\Core\Extension\ThemeHandler
     arguments: ['@app.root', '@config.factory', '@extension.list.theme']
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index 70157580d4..089c271daa 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -369,12 +369,14 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
     }
 
     if ($uninstall_dependents) {
+      $theme_list = \Drupal::service('extension.list.theme')->getList();
+
       // Add dependent modules to the list. The new modules will be processed as
       // the foreach loop continues.
       foreach ($module_list as $module => $value) {
         foreach (array_keys($module_data[$module]->required_by) as $dependent) {
-          if (!isset($module_data[$dependent])) {
-            // The dependent module does not exist.
+          if (!isset($module_data[$dependent]) && !isset($theme_list[$dependent])) {
+            // The dependent module or theme does not exist.
             return FALSE;
           }
 
diff --git a/core/lib/Drupal/Core/Extension/ModuleRequiredByThemesUninstallValidator.php b/core/lib/Drupal/Core/Extension/ModuleRequiredByThemesUninstallValidator.php
new file mode 100644
index 0000000000..0598b031e1
--- /dev/null
+++ b/core/lib/Drupal/Core/Extension/ModuleRequiredByThemesUninstallValidator.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Drupal\Core\Extension;
+
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\StringTranslation\TranslationInterface;
+
+/**
+ * Ensures modules cannot be uninstalled if enabled themes depend on them.
+ */
+class ModuleRequiredByThemesUninstallValidator implements ModuleUninstallValidatorInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * The module extension list.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleExtensionList;
+
+  /**
+   * The theme extension list.
+   *
+   * @var \Drupal\Core\Extension\ThemeExtensionList
+   */
+  protected $themeExtensionList;
+
+  /**
+   * Constructs a new ModuleRequiredByThemesUninstallValidator.
+   *
+   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
+   *   The string translation service.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $extension_list_module
+   *   The module extension list.
+   * @param \Drupal\Core\Extension\ThemeExtensionList $extension_list_theme
+   *   The theme extension list.
+   */
+  public function __construct(TranslationInterface $string_translation, ModuleExtensionList $extension_list_module, ThemeExtensionList $extension_list_theme) {
+    $this->stringTranslation = $string_translation;
+    $this->moduleExtensionList = $extension_list_module;
+    $this->themeExtensionList = $extension_list_theme;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validate($module) {
+    $reasons = [];
+
+    $themes_depending_on_module = $this->getThemesDependingOnModule($module);
+    if (!empty($themes_depending_on_module)) {
+      $module_name = $this->moduleExtensionList->get($module)->info['name'];
+      $theme_names = implode(", ", $themes_depending_on_module);
+      $reasons[] = $this->formatPlural(count($themes_depending_on_module),
+        'Required by the theme: @theme_names',
+        'Required by the themes: @theme_names',
+        ['@module_name' => $module_name, '@theme_names' => $theme_names]);
+    }
+
+    return $reasons;
+  }
+
+  /**
+   * Returns themes that depend on a module.
+   *
+   * @param string $module
+   *   The module machine name.
+   *
+   * @return string[]
+   *   An array of the names of themes that depend on $module.
+   */
+  protected function getThemesDependingOnModule($module) {
+    $installed_themes = $this->themeExtensionList->getAllInstalledInfo();
+    $themes_depending_on_module = array_map(function ($theme) use ($module) {
+      if (in_array($module, $theme['dependencies'])) {
+        return $theme['name'];
+      }
+    }, $installed_themes);
+
+    return array_filter($themes_depending_on_module);
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Extension/ThemeExtensionList.php b/core/lib/Drupal/Core/Extension/ThemeExtensionList.php
index 5722d1c2fe..95334a1b5b 100644
--- a/core/lib/Drupal/Core/Extension/ThemeExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ThemeExtensionList.php
@@ -51,6 +51,7 @@ class ThemeExtensionList extends ExtensionList {
     'libraries' => [],
     'libraries_extend' => [],
     'libraries_override' => [],
+    'dependencies' => [],
   ];
 
   /**
@@ -140,6 +141,16 @@ protected function doList() {
     // sub-themes.
     $this->fillInSubThemeData($themes, $sub_themes);
 
+    foreach ($themes as $key => $theme) {
+      // After $theme is processed by buildModuleDependencies(), there is a
+      // `$theme->requires` array containing both module and base theme
+      // dependencies. The module dependencies are copied to their own property
+      // so they are available to operations specific to module dependencies.
+      if (!isset($theme->requires)) {
+        $theme->requires = [];
+      }
+      $themes[$key]->module_dependencies = isset($theme->base_themes) ? array_diff_key($theme->requires, $theme->base_themes) : $theme->requires;
+    }
     return $themes;
   }
 
diff --git a/core/lib/Drupal/Core/Extension/ThemeInstaller.php b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
index e1149e7b66..59adbae578 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
@@ -106,6 +106,8 @@ public function install(array $theme_list, $install_dependencies = TRUE) {
     $extension_config = $this->configFactory->getEditable('core.extension');
 
     $theme_data = $this->themeHandler->rebuildThemeData();
+    $installed_themes = $this->configFactory->get('core.extension')->get('theme') ?: [];
+    $installed_modules = $this->configFactory->get('core.extension')->get('module') ?: [];
 
     if ($install_dependencies) {
       $theme_list = array_combine($theme_list, $theme_list);
@@ -116,16 +118,25 @@ public function install(array $theme_list, $install_dependencies = TRUE) {
       }
 
       // Only process themes that are not installed currently.
-      $installed_themes = $extension_config->get('theme') ?: [];
       if (!$theme_list = array_diff_key($theme_list, $installed_themes)) {
         // Nothing to do. All themes already installed.
         return TRUE;
       }
 
       foreach ($theme_list as $theme => $value) {
-        // Add dependencies to the list. The new themes will be processed as
-        // the parent foreach loop continues.
-        foreach (array_keys($theme_data[$theme]->requires) as $dependency) {
+        $module_dependencies = $theme_data[$theme]->module_dependencies;
+        $theme_dependencies = array_diff_key($theme_data[$theme]->requires, $module_dependencies);
+        $unmet_module_dependencies = array_diff_key($module_dependencies, $installed_modules);
+
+        // Prevent themes with unmet module dependencies from being installed.
+        if (!empty($unmet_module_dependencies)) {
+          $unmet_module_dependencies_list = implode(', ', array_keys($unmet_module_dependencies));
+          throw new MissingDependencyException("Unable to install theme: '$theme' due to unmet module dependencies: '$unmet_module_dependencies_list.'");
+        }
+
+        // Add dependencies to the list of themes to install. The new themes
+        // will be processed as the parent foreach loop continues.
+        foreach (array_keys($theme_dependencies) as $dependency) {
           if (!isset($theme_data[$dependency])) {
             // The dependency does not exist.
             return FALSE;
@@ -147,9 +158,6 @@ public function install(array $theme_list, $install_dependencies = TRUE) {
       arsort($theme_list);
       $theme_list = array_keys($theme_list);
     }
-    else {
-      $installed_themes = $extension_config->get('theme') ?: [];
-    }
 
     $themes_installed = [];
     foreach ($theme_list as $key) {
diff --git a/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php b/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
index ae79b505ea..6f18248cf9 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
@@ -25,6 +25,9 @@ interface ThemeInstallerInterface {
    *
    * @throws \Drupal\Core\Extension\Exception\UnknownExtensionException
    *   Thrown when the theme does not exist.
+   *
+   * @throws \Drupal\Core\Extension\MissingDependencyException
+   *   Thrown when a requested dependency can't be found.
    */
   public function install(array $theme_list, $install_dependencies = TRUE);
 
diff --git a/core/lib/Drupal/Core/ProxyClass/Extension/ModuleRequiredByThemesUninstallValidator.php b/core/lib/Drupal/Core/ProxyClass/Extension/ModuleRequiredByThemesUninstallValidator.php
new file mode 100644
index 0000000000..601f482e4d
--- /dev/null
+++ b/core/lib/Drupal/Core/ProxyClass/Extension/ModuleRequiredByThemesUninstallValidator.php
@@ -0,0 +1,88 @@
+<?php
+// @codingStandardsIgnoreFile
+
+/**
+ * This file was generated via php core/scripts/generate-proxy-class.php 'Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator' "core/lib/Drupal/Core".
+ */
+
+namespace Drupal\Core\ProxyClass\Extension {
+
+    /**
+     * Provides a proxy class for \Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator.
+     *
+     * @see \Drupal\Component\ProxyBuilder
+     */
+    class ModuleRequiredByThemesUninstallValidator implements \Drupal\Core\Extension\ModuleUninstallValidatorInterface
+    {
+
+        use \Drupal\Core\DependencyInjection\DependencySerializationTrait;
+
+        /**
+         * The id of the original proxied service.
+         *
+         * @var string
+         */
+        protected $drupalProxyOriginalServiceId;
+
+        /**
+         * The real proxied service, after it was lazy loaded.
+         *
+         * @var \Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator
+         */
+        protected $service;
+
+        /**
+         * The service container.
+         *
+         * @var \Symfony\Component\DependencyInjection\ContainerInterface
+         */
+        protected $container;
+
+        /**
+         * Constructs a ProxyClass Drupal proxy object.
+         *
+         * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
+         *   The container.
+         * @param string $drupal_proxy_original_service_id
+         *   The service ID of the original service.
+         */
+        public function __construct(\Symfony\Component\DependencyInjection\ContainerInterface $container, $drupal_proxy_original_service_id)
+        {
+            $this->container = $container;
+            $this->drupalProxyOriginalServiceId = $drupal_proxy_original_service_id;
+        }
+
+        /**
+         * Lazy loads the real service from the container.
+         *
+         * @return object
+         *   Returns the constructed real service.
+         */
+        protected function lazyLoadItself()
+        {
+            if (!isset($this->service)) {
+                $this->service = $this->container->get($this->drupalProxyOriginalServiceId);
+            }
+
+            return $this->service;
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function validate($module)
+        {
+            return $this->lazyLoadItself()->validate($module);
+        }
+
+        /**
+         * {@inheritdoc}
+         */
+        public function setStringTranslation(\Drupal\Core\StringTranslation\TranslationInterface $translation)
+        {
+            return $this->lazyLoadItself()->setStringTranslation($translation);
+        }
+
+    }
+
+}
diff --git a/core/modules/system/src/Controller/SystemController.php b/core/modules/system/src/Controller/SystemController.php
index f27cc01eb1..dd16ce349a 100644
--- a/core/modules/system/src/Controller/SystemController.php
+++ b/core/modules/system/src/Controller/SystemController.php
@@ -4,12 +4,14 @@
 
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\Core\Extension\ModuleExtensionList;
 use Drupal\Core\Extension\ThemeHandlerInterface;
 use Drupal\Core\Form\FormBuilderInterface;
 use Drupal\Core\Menu\MenuLinkTreeInterface;
 use Drupal\Core\Menu\MenuTreeParameters;
 use Drupal\Core\Theme\ThemeAccessCheck;
 use Drupal\Core\Url;
+use Drupal\system\ModuleDependencyMessageTrait;
 use Drupal\system\SystemManager;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -18,6 +20,8 @@
  */
 class SystemController extends ControllerBase {
 
+  use ModuleDependencyMessageTrait;
+
   /**
    * System Manager Service.
    *
@@ -53,6 +57,13 @@ class SystemController extends ControllerBase {
    */
   protected $menuLinkTree;
 
+  /**
+   * The module extension list.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleExtensionList;
+
   /**
    * Constructs a new SystemController.
    *
@@ -66,13 +77,20 @@ class SystemController extends ControllerBase {
    *   The theme handler.
    * @param \Drupal\Core\Menu\MenuLinkTreeInterface $menu_link_tree
    *   The menu link tree service.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $module_extension_list
+   *   The module extension list.
    */
-  public function __construct(SystemManager $systemManager, ThemeAccessCheck $theme_access, FormBuilderInterface $form_builder, ThemeHandlerInterface $theme_handler, MenuLinkTreeInterface $menu_link_tree) {
+  public function __construct(SystemManager $systemManager, ThemeAccessCheck $theme_access, FormBuilderInterface $form_builder, ThemeHandlerInterface $theme_handler, MenuLinkTreeInterface $menu_link_tree, ModuleExtensionList $module_extension_list = NULL) {
     $this->systemManager = $systemManager;
     $this->themeAccess = $theme_access;
     $this->formBuilder = $form_builder;
     $this->themeHandler = $theme_handler;
     $this->menuLinkTree = $menu_link_tree;
+    if ($module_extension_list === NULL) {
+      @trigger_error('The extension.list.module service must be passed to ' . __NAMESPACE__ . '\SystemController::__construct. It was added in Drupal 8.9.0 and will be required before Drupal 10.0.0.', E_USER_DEPRECATED);
+      $module_extension_list = \Drupal::service('extension.list.module');
+    }
+    $this->moduleExtensionList = $module_extension_list;
   }
 
   /**
@@ -84,7 +102,8 @@ public static function create(ContainerInterface $container) {
       $container->get('access_check.theme'),
       $container->get('form_builder'),
       $container->get('theme_handler'),
-      $container->get('menu.link_tree')
+      $container->get('menu.link_tree'),
+      $container->get('extension.list.module')
     );
   }
 
@@ -231,9 +250,44 @@ public function themesPage() {
         $theme->incompatible_base = (isset($theme->info['base theme']) && !($theme->base_themes === array_filter($theme->base_themes)));
         // Confirm that the theme engine is available.
         $theme->incompatible_engine = isset($theme->info['engine']) && !isset($theme->owner);
+        // Confirm that module dependencies are available.
+        $theme->incompatible_module = FALSE;
+        // Confirm that the user has permission to enable modules.
+        $theme->insufficient_module_permissions = FALSE;
       }
+
+      // Check module dependencies.
+      if ($theme->module_dependencies) {
+        $modules = $this->moduleExtensionList->getList();
+        foreach ($theme->module_dependencies as $dependency => $dependency_object) {
+          if ($incompatible = $this->checkDependencyMessage($modules, $dependency, $dependency_object)) {
+            $theme->module_dependencies_list[$dependency] = $incompatible;
+            $theme->incompatible_module = TRUE;
+            continue;
+          }
+
+          // Only display visible modules.
+          if (!empty($modules[$dependency]->hidden)) {
+            continue;
+          }
+
+          $module_name = $modules[$dependency]->info['name'];
+          $theme->module_dependencies_list[$dependency] = $modules[$dependency]->status ? $this->t('@module_name', ['@module_name' => $module_name]) : $this->t('@module_name (<span class="admin-disabled">disabled</span>)', ['@module_name' => $module_name]);
+
+          // Create an additional property that contains only disabled module
+          // dependencies. This will determine if it is possible to install the
+          // theme, or if modules must first be enabled.
+          if (!$modules[$dependency]->status) {
+            $theme->module_dependencies_disabled[$dependency] = $module_name;
+            if (!$this->currentUser()->hasPermission('administer modules')) {
+              $theme->insufficient_module_permissions = TRUE;
+            }
+          }
+        }
+      }
+
       $theme->operations = [];
-      if (!empty($theme->status) || !$theme->info['core_incompatible'] && !$theme->incompatible_php && !$theme->incompatible_base && !$theme->incompatible_engine) {
+      if (!empty($theme->status) || !$theme->info['core_incompatible'] && !$theme->incompatible_php && !$theme->incompatible_base && !$theme->incompatible_engine && !$theme->incompatible_module && empty($theme->module_dependencies_disabled)) {
         // Create the operations links.
         $query['theme'] = $theme->getName();
         if ($this->themeAccess->checkAccess($theme->getName())) {
diff --git a/core/modules/system/src/Form/ModulesListForm.php b/core/modules/system/src/Form/ModulesListForm.php
index f32dad0909..45a57d7d12 100644
--- a/core/modules/system/src/Form/ModulesListForm.php
+++ b/core/modules/system/src/Form/ModulesListForm.php
@@ -17,6 +17,7 @@
 use Drupal\Core\Session\AccountInterface;
 use Drupal\user\PermissionHandlerInterface;
 use Drupal\Core\Url;
+use Drupal\system\ModuleDependencyMessageTrait;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -31,6 +32,8 @@
  */
 class ModulesListForm extends FormBase {
 
+  use ModuleDependencyMessageTrait;
+
   /**
    * The current user.
    *
@@ -326,38 +329,19 @@ protected function buildRow(array $modules, Extension $module, $distribution) {
     // If this module requires other modules, add them to the array.
     /** @var \Drupal\Core\Extension\Dependency $dependency_object */
     foreach ($module->requires as $dependency => $dependency_object) {
-      if (!isset($modules[$dependency])) {
-        $row['#requires'][$dependency] = $this->t('@module (<span class="admin-missing">missing</span>)', ['@module' => $dependency]);
-        $row['enable']['#disabled'] = TRUE;
+      // Only display missing or visible modules.
+      if (!empty($modules[$dependency]->hidden)) {
+        continue;
       }
-      // Only display visible modules.
-      elseif (empty($modules[$dependency]->hidden)) {
-        $name = $modules[$dependency]->info['name'];
-        // Disable the module's checkbox if it is incompatible with the
-        // dependency's version.
-        if (!$dependency_object->isCompatible(str_replace(\Drupal::CORE_COMPATIBILITY . '-', '', $modules[$dependency]->info['version']))) {
-          $row['#requires'][$dependency] = $this->t('@module (@constraint) (<span class="admin-missing">incompatible with</span> version @version)', [
-            '@module' => $name,
-            '@constraint' => $dependency_object->getConstraintString(),
-            '@version' => $modules[$dependency]->info['version'],
-          ]);
-          $row['enable']['#disabled'] = TRUE;
-        }
-        // Disable the checkbox if the dependency is incompatible with this
-        // version of Drupal core.
-        elseif ($modules[$dependency]->info['core_incompatible']) {
-          $row['#requires'][$dependency] = $this->t('@module (<span class="admin-missing">incompatible with</span> this version of Drupal core)', [
-            '@module' => $name,
-          ]);
-          $row['enable']['#disabled'] = TRUE;
-        }
-        elseif ($modules[$dependency]->status) {
-          $row['#requires'][$dependency] = $this->t('@module', ['@module' => $name]);
-        }
-        else {
-          $row['#requires'][$dependency] = $this->t('@module (<span class="admin-disabled">disabled</span>)', ['@module' => $name]);
-        }
+
+      if ($incompatible = $this->checkDependencyMessage($modules, $dependency, $dependency_object)) {
+        $row['#requires'][$dependency] = $incompatible;
+        $row['enable']['#disabled'] = TRUE;
+        continue;
       }
+
+      $name = $modules[$dependency]->info['name'];
+      $row['#requires'][$dependency] = $modules[$dependency]->status ? $this->t('@module', ['@module' => $name]) : $this->t('@module (<span class="admin-disabled">disabled</span>)', ['@module' => $name]);
     }
 
     // If this module is required by other modules, list those, and then make it
diff --git a/core/modules/system/src/ModuleDependencyMessageTrait.php b/core/modules/system/src/ModuleDependencyMessageTrait.php
new file mode 100644
index 0000000000..31d3f12c69
--- /dev/null
+++ b/core/modules/system/src/ModuleDependencyMessageTrait.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\system;
+
+use Drupal\Core\Extension\Dependency;
+
+/**
+ * Messages for missing or incompatible dependencies on modules.
+ *
+ * @internal
+ */
+trait ModuleDependencyMessageTrait {
+
+  /**
+   * Provides messages for missing modules or incompatible dependencies.
+   *
+   * @param array $modules
+   *   The list of existing modules.
+   * @param string $dependency
+   *   The module dependency to check.
+   * @param \Drupal\Core\Extension\Dependency $dependency_object
+   *   Dependency object used for comparing version requirement data.
+   *
+   * @return string|null
+   *   NULL if compatible, otherwise a string describing the incompatibility.
+   */
+  public function checkDependencyMessage(array $modules, $dependency, Dependency $dependency_object) {
+    if (!isset($modules[$dependency])) {
+      return $this->t('@module_name (<span class="admin-missing">missing</span>)', ['@module_name' => $dependency]);
+    }
+    else {
+      $module_name = $modules[$dependency]->info['name'];
+
+      // Check if the module is compatible with the installed version of core.
+      if ($modules[$dependency]->info['core_incompatible']) {
+        return $this->t('@module_name (<span class="admin-missing">incompatible with</span> this version of Drupal core)', [
+          '@module_name' => $module_name,
+        ]);
+      }
+
+      // Check if the module is incompatible with the dependency constraints.
+      $version = str_replace(\Drupal::CORE_COMPATIBILITY . '-', '', $modules[$dependency]->info['version']);
+      if (!$dependency_object->isCompatible($version)) {
+        $constraint_string = $dependency_object->getConstraintString();
+        return $this->t('@module_name (<span class="admin-missing">incompatible with</span> version @version)', [
+          '@module_name' => "$module_name ($constraint_string)",
+          '@version' => $modules[$dependency]->info['version'],
+        ]);
+      }
+    }
+  }
+
+}
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 661677b51a..206ed3cdf3 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -9,6 +9,7 @@
 use Drupal\Core\Link;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Url;
 
 /**
  * Prepares variables for administrative content block templates.
@@ -123,7 +124,7 @@ function template_preprocess_system_admin_index(&$variables) {
  *     - version: The version of the module.
  *     - links: Administration links provided by the module.
  *     - #requires: A list of modules that the project requires.
- *     - #required_by: A list of modules that require the project.
+ *     - #required_by: A list of modules and themes that require the project.
  *     - #attributes: A list of attributes for the module wrapper.
  *
  * @see \Drupal\system\Form\ModulesListForm
@@ -131,6 +132,18 @@ function template_preprocess_system_admin_index(&$variables) {
 function template_preprocess_system_modules_details(&$variables) {
   $form = $variables['form'];
 
+  // Identify modules that are depended on by themes.
+  // Added here instead of ModuleHandler to avoid recursion.
+  $themes = \Drupal::service('extension.list.theme')->getList();
+  foreach ($themes as $theme) {
+    foreach ($theme->info['dependencies'] as $dependency) {
+      if (isset($form[$dependency])) {
+        // Add themes to the module's required by list.
+        $form[$dependency]['#required_by'][] = $theme->info['name'] . ' (' . t('Theme') . ')' . (!$theme->status ? ' (' . t('Disabled') . ')' : '');
+      }
+    }
+  }
+
   $variables['modules'] = [];
   // Iterate through all the modules, which are children of this element.
   foreach (Element::children($form) as $key) {
@@ -291,6 +304,12 @@ function template_preprocess_system_themes_page(&$variables) {
       $current_theme['is_default'] = $theme->is_default;
       $current_theme['is_admin'] = $theme->is_admin;
 
+      $current_theme['module_dependencies'] = !empty($theme->module_dependencies_list) ? [
+        '#theme' => 'item_list',
+        '#items' => $theme->module_dependencies_list,
+        '#context' => ['list_style' => 'comma-list'],
+      ] : [];
+
       // Make sure to provide feedback on compatibility.
       $current_theme['incompatible'] = '';
       if (!empty($theme->info['core_incompatible'])) {
@@ -311,6 +330,20 @@ function template_preprocess_system_themes_page(&$variables) {
       elseif (!empty($theme->incompatible_engine)) {
         $current_theme['incompatible'] = t('This theme requires the theme engine @theme_engine to operate correctly.', ['@theme_engine' => $theme->info['engine']]);
       }
+      elseif (!empty($theme->incompatible_module)) {
+        $current_theme['incompatible'] = t('This theme requires the listed modules to operate correctly.');
+      }
+      elseif (!empty($theme->module_dependencies_disabled)) {
+        if (!empty($theme->insufficient_module_permissions)) {
+          $current_theme['incompatible'] = t('This theme requires the listed modules to operate correctly. They must first be enabled by a user with permissions to do so.');
+        }
+        else {
+          $modules_url = (string) Url::fromRoute('system.modules_list')->toString();
+          $current_theme['incompatible'] = t('This theme requires the listed modules to operate correctly. They must first be enabled via the <a href=":modules_url">Extend page</a>.', [
+            ':modules_url' => $modules_url,
+          ]);
+        }
+      }
 
       // Build operation links.
       $current_theme['operations'] = [
diff --git a/core/modules/system/templates/system-themes-page.html.twig b/core/modules/system/templates/system-themes-page.html.twig
index 6e65d7641b..6916151f22 100644
--- a/core/modules/system/templates/system-themes-page.html.twig
+++ b/core/modules/system/templates/system-themes-page.html.twig
@@ -22,6 +22,7 @@
  *     - notes: Identifies what context this theme is being used in, e.g.,
  *       default theme, admin theme.
  *     - incompatible: Text describing any compatibility issues.
+ *     - module_dependencies: A list of modules that this theme requires.
  *     - operations: A list of operation links, e.g., Settings, Enable, Disable,
  *       etc. these links should only be displayed if the theme is compatible.
  *
@@ -62,6 +63,9 @@
               {%- endif -%}
             </h3>
             <div class="theme-info__description">{{ theme.description }}</div>
+            {% if theme.module_dependencies %}
+              <div class="theme-info__requires">Requires: {{ theme.module_dependencies }}</div>
+            {% endif %}
             {# Display operation links if the theme is compatible. #}
             {% if theme.incompatible %}
               <div class="incompatible">{{ theme.incompatible }}</div>
diff --git a/core/modules/system/tests/src/Functional/Form/ModulesListFormWebTest.php b/core/modules/system/tests/src/Functional/Form/ModulesListFormWebTest.php
index a210cd37a9..cef12ffcc7 100644
--- a/core/modules/system/tests/src/Functional/Form/ModulesListFormWebTest.php
+++ b/core/modules/system/tests/src/Functional/Form/ModulesListFormWebTest.php
@@ -33,13 +33,7 @@ protected function setUp() {
    * Tests the module list form.
    */
   public function testModuleListForm() {
-    $this->drupalLogin(
-      $this->drupalCreateUser(
-        ['administer modules', 'administer permissions']
-      )
-    );
-    $this->drupalGet('admin/modules');
-    $this->assertResponse('200');
+    $this->createUserAdministerModules();
 
     // Check that system_test's configure link was rendered correctly.
     $this->assertFieldByXPath("//a[contains(@href, '/system-test/configure/bar') and text()='Configure ']/span[contains(@class, 'visually-hidden') and text()='the System test module']");
@@ -65,13 +59,7 @@ public function testModulesListFormWithInvalidInfoFile() {
     mkdir($path, 0777, TRUE);
     file_put_contents("$path/broken.info.yml", $broken_info_yml);
 
-    $this->drupalLogin(
-      $this->drupalCreateUser(
-        ['administer modules', 'administer permissions']
-      )
-    );
-    $this->drupalGet('admin/modules');
-    $this->assertSession()->statusCodeEquals(200);
+    $this->createUserAdministerModules();
 
     // Confirm that the error message is shown.
     $this->assertSession()
@@ -81,4 +69,33 @@ public function testModulesListFormWithInvalidInfoFile() {
     $this->assertSession()->elementExists('xpath', '//input[@name="text"]');
   }
 
+  /**
+   * Confirm that module 'Required By' descriptions include dependent themes.
+   */
+  public function testRequiredByThemeMessage() {
+    $this->createUserAdministerModules();
+    $module_theme_depends_on_description = $this->getSession()->getPage()->findAll('css', '#edit-modules-test-module-required-by-theme-enable-description .admin-requirements li:contains("Test Theme Depending on Modules (Theme) (Disabled)")');
+
+    // Confirm that that 'Test Theme Depending on Modules' is listed as being
+    // required by the module 'Test Module Required by Theme'.
+    $this->assertCount(1, $module_theme_depends_on_description);
+
+    // Confirm that the required by message does not appear anywhere else.
+    $this->assertSession()->pageTextContains('Test Theme Depending on Modules (Theme) (Disabled)');
+  }
+
+  /**
+   * Creates user that can administer modules then visits `admin/modules`.
+   */
+  protected function createUserAdministerModules() {
+    $this->drupalLogin(
+      $this->drupalCreateUser(
+        ['administer modules', 'administer permissions']
+      )
+    );
+
+    $this->drupalGet('admin/modules');
+    $this->assertSession()->statusCodeEquals(200);
+  }
+
 }
diff --git a/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
new file mode 100644
index 0000000000..5291c27e16
--- /dev/null
+++ b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
@@ -0,0 +1,319 @@
+<?php
+
+namespace Drupal\Tests\system\Functional\Theme;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests the theme UI.
+ *
+ * @group Theme
+ */
+class ThemeUiTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->drupalLogin($this->adminUser = $this->drupalCreateUser([
+      'administer themes',
+      'administer modules',
+    ]));
+  }
+
+  /**
+   * Tests permissions for enabling themes depending on disabled modules.
+   */
+  public function testModulePermissions() {
+    // Log in as a user without permission to enable modules.
+    $this->drupalLogin($this->drupalCreateUser([
+      'administer themes',
+    ]));
+    $this->drupalGet('admin/appearance');
+
+    // The links to install a theme that would enable modules should be replaced
+    // by this message.
+    $this->assertSession()->pageTextContains('This theme requires the listed modules to operate correctly. They must first be enabled by a user with permissions to do so.');
+
+    // The install page should not be reachable.
+    $this->drupalGet('admin/appearance/install?theme=test_theme_depending_on_modules');
+    $this->assertSession()->statusCodeEquals(404);
+
+    $this->drupalLogin($this->drupalCreateUser([
+      'administer themes',
+      'administer modules',
+    ]));
+    $this->drupalGet('admin/appearance');
+    $this->assertSession()->pageTextNotContains('This theme requires the listed modules to operate correctly. They must first be enabled by a user with permissions to do so.');
+  }
+
+  /**
+   * Tests installing a theme with module dependencies.
+   *
+   * @dataProvider providerTestThemeInstallWithModuleDependencies
+   */
+  public function testThemeInstallWithModuleDependencies($theme_name, array $first_expected_required_list_items, array $first_module_enable, array $first_confirm_checked, array $second_expected_required_list_items, array $second_module_enable, array $second_confirm_checked, array $module_names, array $required_by_messages, $module_uninstall_message, $base_theme_to_uninstall, array $base_theme_module_names, $base_theme_module_uninstall_message) {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+    $this->drupalGet('admin/appearance');
+
+    $this->assertUninstallableTheme($first_expected_required_list_items, $theme_name);
+
+    // Enable one of the two required modules.
+    $this->drupalPostForm('admin/modules', $first_module_enable, 'Install');
+    foreach ($first_confirm_checked as $selector) {
+      $this->assertSession()->elementExists('css', $selector);
+    }
+
+    $this->drupalGet('admin/appearance');
+
+    // Confirm the theme is still uninstallable due to a remaining module
+    // dependency.
+    $this->assertUninstallableTheme($second_expected_required_list_items, $theme_name);
+    $this->drupalPostForm('admin/modules', $second_module_enable, 'Install');
+    foreach ($second_confirm_checked as $selector) {
+      $this->assertSession()->elementExists('css', $selector);
+    }
+
+    // The theme should now be installable, so install it.
+    $this->drupalGet('admin/appearance');
+    $page->clickLink("Install $theme_name theme");
+    $assert_session->addressEquals('admin/appearance');
+    $assert_session->pageTextContains("The $theme_name theme has been installed");
+
+    // Confirm that the dependee modules can't be uninstalled because an enabled
+    // theme depends on them.
+    $this->drupalGet('admin/modules/uninstall');
+    foreach ($module_names as $attribute) {
+      $assert_session->elementExists('css', "[name=\"uninstall[$attribute]\"][disabled]");
+    }
+    foreach ($required_by_messages as $selector => $message) {
+      $assert_session->elementTextContains('css', $selector, $message);
+    }
+
+    // Uninstall the theme that depends on the modules, and confirm the modules
+    // can now be uninstalled.
+    $this->uninstallTheme($theme_name);
+    $this->drupalGet('admin/modules/uninstall');
+
+    // Only attempt to uninstall modules not required by the base theme.
+    $modules_to_uninstall = array_diff($module_names, $base_theme_module_names);
+    $this->uninstallModules($modules_to_uninstall, $module_uninstall_message);
+
+    if (!empty($base_theme_to_uninstall)) {
+      $base_theme_name = $base_theme_to_uninstall;
+      $this->uninstallTheme($base_theme_name);
+      $this->drupalGet('admin/modules/uninstall');
+      $this->uninstallModules($base_theme_module_names, $base_theme_module_uninstall_message);
+    }
+  }
+
+  /**
+   * Uninstalls modules via the admin UI.
+   *
+   * @param string[] $module_names
+   *   An array of module machine names.
+   * @param string $confirmation_message_list
+   *   The list of modules included in the confirmation.
+   */
+  protected function uninstallModules(array $module_names, $confirmation_message_list) {
+    $assert_session = $this->assertSession();
+    $this->drupalGet('admin/modules/uninstall');
+    foreach ($module_names as $attribute) {
+      $assert_session->elementExists('css', "[name=\"uninstall[$attribute]\"]:not([disabled])");
+    }
+    $to_uninstall = [];
+    foreach ($module_names as $attribute) {
+      $to_uninstall["uninstall[$attribute]"] = 1;
+    }
+    if (!empty($to_uninstall)) {
+      $this->drupalPostForm('admin/modules/uninstall', $to_uninstall, 'Uninstall');
+      $confirmation_message = 'The following modules will be completely uninstalled from your site, and all data from these modules will be lost!' . $confirmation_message_list . 'Would you like to continue with uninstalling the above?';
+      $assert_session->pageTextContains($confirmation_message);
+      $this->getSession()->getPage()->pressButton('Uninstall');
+      $assert_session->pageTextContains('The selected modules have been uninstalled.');
+    }
+  }
+
+  /**
+   * Uninstalls a theme via the admin UI.
+   *
+   * @param string $theme_name
+   *   The theme name.
+   */
+  protected function uninstallTheme($theme_name) {
+    $this->drupalGet('admin/appearance');
+    $this->clickLink("Uninstall $theme_name theme");
+    $this->assertSession()->pageTextContains("The $theme_name theme has been uninstalled.");
+  }
+
+  /**
+   * Data provider for testThemeInstallWithModuleDependencies().
+   */
+  public function providerTestThemeInstallWithModuleDependencies() {
+    return [
+      'test theme with a module dependency and base theme with a different module dependency' => [
+        'theme_name' => 'Test Theme with a Module Dependency and Base Theme with a Different Module Dependency',
+        'first_expected_required_list_items' => [
+          'Help (disabled)',
+          'Test Module Required by Theme (disabled)',
+          'Test Another Module Required by Theme (disabled)',
+        ],
+        'first_module_enable' => [
+          'modules[test_module_required_by_theme][enable]' => 1,
+          'modules[test_another_module_required_by_theme][enable]' => 1,
+        ],
+        'first_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+          '#edit-modules-test-another-module-required-by-theme-enable[checked]',
+        ],
+        'second_expected_required_list_items' => [
+          'Help (disabled)',
+          'Test Module Required by Theme',
+          'Test Another Module Required by Theme',
+        ],
+        'second_module_enable' => [
+          'modules[help][enable]' => 1,
+        ],
+        'second_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+          '#edit-modules-test-another-module-required-by-theme-enable[checked]',
+          '#edit-modules-help-enable[checked]',
+        ],
+        'module_names' => [
+          'help',
+          'test_module_required_by_theme',
+          'test_another_module_required_by_theme',
+        ],
+        'required_by_messages' => [
+          '[data-drupal-selector="edit-test-another-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+          '[data-drupal-selector="edit-test-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+          '[data-drupal-selector="edit-help"] .item-list' => 'Required by the theme: Test Theme with a Module Dependency and Base Theme with a Different Module Dependency',
+        ],
+        'module_uninstall_message' => 'help',
+        'base_theme_to_uninstall' => 'Test Theme Depending on Modules',
+        'base_theme_module_names' => [
+          'test_module_required_by_theme',
+          'test_another_module_required_by_theme',
+        ],
+        'base_theme_module_uninstall_message' => 'Test Another Module Required by ThemeTest Module Required by Theme',
+      ],
+      'Test Theme Depending on Modules' => [
+        'theme_name' => 'Test Theme Depending on Modules',
+        'first_expected_required_list_items' => [
+          'Test Module Required by Theme (disabled)',
+          'Test Another Module Required by Theme (disabled)',
+        ],
+        'first_module_enable' => [
+          'modules[test_module_required_by_theme][enable]' => 1,
+        ],
+        'first_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+        ],
+        'second_expected_required_list_items' => [
+          'Test Module Required by Theme',
+          'Test Another Module Required by Theme (disabled)',
+        ],
+        'second_module_enable' => [
+          'modules[test_another_module_required_by_theme][enable]' => 1,
+        ],
+        'second_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+          '#edit-modules-test-another-module-required-by-theme-enable[checked]',
+        ],
+        'module_names' => [
+          'test_module_required_by_theme',
+          'test_another_module_required_by_theme',
+        ],
+        'required_by_messages' => [
+          '[data-drupal-selector="edit-test-another-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+          '[data-drupal-selector="edit-test-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+        ],
+        'module_uninstall_message' => 'Test Another Module Required by ThemeTest Module Required by Theme',
+        'base_theme_to_uninstall' => '',
+        'base_theme_module_names' => [],
+        'base_theme_module_uninstall_message' => '',
+      ],
+      'test theme with a base theme depending on modules' => [
+        'theme_name' => 'Test Theme with a Base Theme Depending on Modules',
+        'first_expected_required_list_items' => [
+          'Test Module Required by Theme (disabled)',
+          'Test Another Module Required by Theme (disabled)',
+        ],
+        'first_module_enable' => [
+          'modules[test_module_required_by_theme][enable]' => 1,
+        ],
+        'first_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+        ],
+        'second_expected_required_list_items' => [
+          'Test Module Required by Theme',
+          'Test Another Module Required by Theme (disabled)',
+        ],
+        'second_module_enable' => [
+          'modules[test_another_module_required_by_theme][enable]' => 1,
+        ],
+        'second_confirm_checked' => [
+          '#edit-modules-test-module-required-by-theme-enable[checked]',
+          '#edit-modules-test-another-module-required-by-theme-enable[checked]',
+        ],
+        'module_names' => [
+          'test_module_required_by_theme',
+          'test_another_module_required_by_theme',
+        ],
+        'required_by_messages' => [
+          '[data-drupal-selector="edit-test-another-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+          '[data-drupal-selector="edit-test-module-required-by-theme"] .item-list' => 'Required by the theme: Test Theme Depending on Modules',
+        ],
+        'module_uninstall_message' => '',
+        'base_theme_to_uninstall' => 'Test Theme Depending on Modules',
+        'base_theme_module_names' => [
+          'test_module_required_by_theme',
+          'test_another_module_required_by_theme',
+        ],
+        'base_theme_module_uninstall_message' => 'Test Another Module Required by ThemeTest Module Required by Theme',
+      ],
+    ];
+  }
+
+  /**
+   * Checks related to uninstallable themes due to module dependencies.
+   *
+   * @param string[] $expected_requires_list_items
+   *   The modules listed as being required to install the theme.
+   * @param string $theme_name
+   *   The name of the theme.
+   */
+  protected function assertUninstallableTheme(array $expected_requires_list_items, $theme_name) {
+    $theme_container = $this->getSession()->getPage()->find('css', "h3:contains(\"$theme_name\")")->getParent();
+    $requires_list_items = $theme_container->findAll('css', '.theme-info__requires li');
+    $this->assertCount(count($expected_requires_list_items), $requires_list_items);
+
+    foreach ($requires_list_items as $key => $item) {
+      $this->assertSame($expected_requires_list_items[$key], $item->getText());
+    }
+
+    $incompatible = $theme_container->find('css', '.incompatible');
+    $expected_incompatible_text = 'This theme requires the listed modules to operate correctly. They must first be enabled via the Extend page.';
+    $this->assertSame($expected_incompatible_text, $incompatible->getText());
+    $this->assertFalse($theme_container->hasLink('Install Test Theme Depending on Modules theme'));
+  }
+
+  /**
+   * Tests installing a theme with missing module dependencies.
+   */
+  public function testInstallModuleWithMissingDependencies() {
+    $this->drupalGet('admin/appearance');
+    $theme_container = $this->getSession()->getPage()->find('css', 'h3:contains("Test Theme Depending on Nonexisting Module")')->getParent();
+    $this->assertContains('missing', $theme_container->getText());
+    $this->assertContains('This theme requires the listed modules to operate correctly.', $theme_container->getText());
+  }
+
+}
diff --git a/core/modules/system/tests/themes/test_theme_depending_nonexisting_module/test_theme_depending_on_nonexisting_module.info.yml b/core/modules/system/tests/themes/test_theme_depending_nonexisting_module/test_theme_depending_on_nonexisting_module.info.yml
new file mode 100644
index 0000000000..43c8ed477b
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_depending_nonexisting_module/test_theme_depending_on_nonexisting_module.info.yml
@@ -0,0 +1,7 @@
+name: Test Theme Depending on Nonexisting Module
+type: theme
+core: 8.x
+base theme: stark
+version: VERSION
+dependencies:
+  - test_module_non_existing
diff --git a/core/modules/system/tests/themes/test_theme_depending_on_modules/test_another_module_required_by_theme/test_another_module_required_by_theme.info.yml b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_another_module_required_by_theme/test_another_module_required_by_theme.info.yml
new file mode 100644
index 0000000000..4527338d46
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_another_module_required_by_theme/test_another_module_required_by_theme.info.yml
@@ -0,0 +1,5 @@
+name: Test Another Module Required by Theme
+type: module
+core: 8.x
+package: Testing
+version: VERSION
diff --git a/core/modules/system/tests/themes/test_theme_depending_on_modules/test_module_required_by_theme/test_module_required_by_theme.info.yml b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_module_required_by_theme/test_module_required_by_theme.info.yml
new file mode 100644
index 0000000000..75fcd17ae5
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_module_required_by_theme/test_module_required_by_theme.info.yml
@@ -0,0 +1,5 @@
+name: Test Module Required by Theme
+type: module
+core: 8.x
+package: Testing
+version: VERSION
diff --git a/core/modules/system/tests/themes/test_theme_depending_on_modules/test_theme_depending_on_modules.info.yml b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_theme_depending_on_modules.info.yml
new file mode 100644
index 0000000000..a20675c742
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_depending_on_modules/test_theme_depending_on_modules.info.yml
@@ -0,0 +1,7 @@
+name: Test Theme Depending on Modules
+type: theme
+core: 8.x
+base theme: stark
+dependencies:
+  - test_module_required_by_theme
+  - test_another_module_required_by_theme
diff --git a/core/modules/system/tests/themes/test_theme_mixed_module_dependencies/test_theme_mixed_module_dependencies.info.yml b/core/modules/system/tests/themes/test_theme_mixed_module_dependencies/test_theme_mixed_module_dependencies.info.yml
new file mode 100644
index 0000000000..19aa00e49c
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_mixed_module_dependencies/test_theme_mixed_module_dependencies.info.yml
@@ -0,0 +1,6 @@
+name: Test Theme with a Module Dependency and Base Theme with a Different Module Dependency
+type: theme
+core: 8.x
+base theme: test_theme_depending_on_modules
+dependencies:
+  - help
diff --git a/core/modules/system/tests/themes/test_theme_with_a_base_theme_depending_on_modules/test_theme_with_a_base_theme_depending_on_modules.info.yml b/core/modules/system/tests/themes/test_theme_with_a_base_theme_depending_on_modules/test_theme_with_a_base_theme_depending_on_modules.info.yml
new file mode 100644
index 0000000000..91391fdac8
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_with_a_base_theme_depending_on_modules/test_theme_with_a_base_theme_depending_on_modules.info.yml
@@ -0,0 +1,4 @@
+name: Test Theme with a Base Theme Depending on Modules
+type: theme
+core: 8.x
+base theme: test_theme_depending_on_modules
diff --git a/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php b/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
index c8dd0337a8..7ff1ec3a12 100644
--- a/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
@@ -4,6 +4,8 @@
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\Extension\ExtensionNameLengthException;
+use Drupal\Core\Extension\MissingDependencyException;
+use Drupal\Core\Extension\ModuleUninstallValidatorException;
 use Drupal\Core\Extension\Exception\UnknownExtensionException;
 use Drupal\KernelTests\KernelTestBase;
 
@@ -137,6 +139,69 @@ public function testInstallNameTooLong() {
     }
   }
 
+  /**
+   * Tests installing a theme with unmet module dependencies.
+   *
+   * @dataProvider providerTestInstallThemeWithUnmetModuleDependencies
+   */
+  public function testInstallThemeWithUnmetModuleDependencies($theme_name, $missing_dependencies, $installed_modules) {
+    $this->container->get('module_installer')->install($installed_modules);
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertEmpty(array_keys($themes));
+    $this->expectException(MissingDependencyException::class);
+    $this->expectExceptionMessage("Unable to install theme: '$theme_name' due to unmet module dependencies: '$missing_dependencies'");
+    $this->themeInstaller()->install([$theme_name]);
+  }
+
+  /**
+   * Data provider for testInstallThemeWithUnmetModuleDependencies().
+   */
+  public function providerTestInstallThemeWithUnmetModuleDependencies() {
+    return [
+      'theme with uninstalled module dependencies' => [
+        'test_theme_depending_on_modules',
+        'test_module_required_by_theme, test_another_module_required_by_theme.',
+        [],
+      ],
+      'theme with a base theme with uninstalled module dependencies' => [
+        'test_theme_with_a_base_theme_depending_on_modules',
+        'test_module_required_by_theme, test_another_module_required_by_theme.',
+        [],
+      ],
+      'theme and base theme have uninstalled module dependencies' => [
+        'test_theme_mixed_module_dependencies',
+        'help, test_module_required_by_theme, test_another_module_required_by_theme.',
+        [],
+      ],
+      'theme with already installed module dependencies, base theme module dependencies are not installed' => [
+        'test_theme_mixed_module_dependencies',
+        'test_module_required_by_theme, test_another_module_required_by_theme.',
+        ['help'],
+      ],
+      'theme with module dependencies not installed, base theme module dependencies are already installed, ' => [
+        'test_theme_mixed_module_dependencies',
+        'help.',
+        ['test_module_required_by_theme', 'test_another_module_required_by_theme'],
+      ],
+    ];
+  }
+
+  /**
+   * Tests installing a theme with module dependencies that are met.
+   */
+  public function testInstallThemeWithMetModuleDependencies() {
+    $name = 'test_theme_depending_on_modules';
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]));
+    $this->container->get('module_installer')->install(['test_module_required_by_theme', 'test_another_module_required_by_theme']);
+    $this->themeInstaller()->install([$name]);
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->expectException(ModuleUninstallValidatorException::class);
+    $this->expectExceptionMessage('The following reasons prevent the modules from being uninstalled: Required by the theme: Test Theme Depending on Modules');
+    $this->container->get('module_installer')->uninstall(['test_module_required_by_theme']);
+  }
+
   /**
    * Tests uninstalling the default theme.
    */
diff --git a/core/tests/Drupal/Tests/Core/Extension/ModuleRequiredByThemesUninstallValidatorTest.php b/core/tests/Drupal/Tests/Core/Extension/ModuleRequiredByThemesUninstallValidatorTest.php
new file mode 100644
index 0000000000..71537340a3
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Extension/ModuleRequiredByThemesUninstallValidatorTest.php
@@ -0,0 +1,161 @@
+<?php
+
+namespace Drupal\Tests\Core\Extension;
+
+use Drupal\Core\Extension\ModuleExtensionList;
+use Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator;
+use Drupal\Core\Extension\ThemeExtensionList;
+use Drupal\Tests\AssertHelperTrait;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator
+ * @group Extension
+ */
+class ModuleRequiredByThemesUninstallValidatorTest extends UnitTestCase {
+
+  use AssertHelperTrait;
+
+  /**
+   * Instance of ModuleRequiredByThemesUninstallValidator.
+   *
+   * @var \Drupal\Core\Extension\ModuleRequiredByThemesUninstallValidator|\PHPUnit\Framework\MockObject\MockObject
+   */
+  protected $moduleRequiredByThemeUninstallValidator;
+
+  /**
+   * Mock of ModuleExtensionList.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList|\PHPUnit\Framework\MockObject\MockObject
+   */
+  protected $moduleExtensionList;
+
+  /**
+   * Mock of ThemeExtensionList.
+   *
+   * @var \Drupal\Core\Extension\ThemeExtensionList|\PHPUnit\Framework\MockObject\MockObject
+   */
+  protected $themeExtensionList;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->moduleExtensionList = $this->prophesize(ModuleExtensionList::class);
+    $this->themeExtensionList = $this->prophesize(ThemeExtensionList::class);
+    $this->moduleRequiredByThemeUninstallValidator = new ModuleRequiredByThemesUninstallValidator($this->getStringTranslationStub(), $this->moduleExtensionList->reveal(), $this->themeExtensionList->reveal());
+  }
+
+  /**
+   * @covers ::validate
+   */
+  public function testValidateNoThemeDependency() {
+    $this->themeExtensionList->getAllInstalledInfo()->willReturn([
+      'stable' => [
+        'name' => 'Stable',
+        'dependencies' => [],
+      ],
+      'claro' => [
+        'name' => 'Claro',
+        'dependencies' => [],
+      ],
+    ]);
+
+    $module = $this->randomMachineName();
+    $expected = [];
+    $reasons = $this->moduleRequiredByThemeUninstallValidator->validate($module);
+    $this->assertSame($expected, $reasons);
+  }
+
+  /**
+   * @covers ::validate
+   */
+  public function testValidateOneThemeDependency() {
+    $module = 'single_module';
+    $module_name = 'Single Module';
+    $theme = 'one_theme';
+    $theme_name = 'One Theme';
+    $this->themeExtensionList->getAllInstalledInfo()->willReturn([
+      'stable' => [
+        'name' => 'Stable',
+        'dependencies' => [],
+      ],
+      'claro' => [
+        'name' => 'Claro',
+        'dependencies' => [],
+      ],
+      $theme => [
+        'name' => $theme_name,
+        'dependencies' => [
+          $module,
+        ],
+      ],
+    ]);
+
+    $this->moduleExtensionList->get($module)->willReturn((object) [
+      'info' => [
+        'name' => $module_name,
+      ],
+    ]);
+
+    $expected = [
+      "Required by the theme: $theme_name",
+    ];
+
+    $reasons = $this->moduleRequiredByThemeUninstallValidator->validate($module);
+    $this->assertSame($expected, $this->castSafeStrings($reasons));
+  }
+
+  /**
+   * @covers ::validate
+   */
+  public function testValidateTwoThemeDependencies() {
+    $module = 'popular_module';
+    $module_name = 'Popular Module';
+    $theme1 = 'first_theme';
+    $theme2 = 'second_theme';
+    $theme_name_1 = 'First Theme';
+    $theme_name_2 = 'Second Theme';
+    $this->themeExtensionList->getAllInstalledInfo()->willReturn([
+      'stable' => [
+        'name' => 'Stable',
+        'dependencies' => [],
+      ],
+      'claro' => [
+        'name' => 'Claro',
+        'dependencies' => [],
+      ],
+      $theme1 => [
+        'name' => $theme_name_1,
+        'dependencies' => [
+          $module,
+        ],
+      ],
+      $theme2 => [
+        'name' => $theme_name_2,
+        'dependencies' => [
+          $module,
+        ],
+      ],
+    ]);
+
+    $this->moduleExtensionList->get($module)->willReturn((object) [
+      'info' => [
+        'name' => $module_name,
+      ],
+    ]);
+
+    $expected = [
+      "Required by the themes: $theme_name_1, $theme_name_2",
+    ];
+
+    $reasons = $this->moduleRequiredByThemeUninstallValidator->validate($module);
+    $this->assertSame($expected, $this->castSafeStrings($reasons));
+  }
+
+}
+
+if (!defined('DRUPAL_MINIMUM_PHP')) {
+  define('DRUPAL_MINIMUM_PHP', '7.0.8');
+}
diff --git a/core/themes/claro/templates/system-themes-page.html.twig b/core/themes/claro/templates/system-themes-page.html.twig
index 1108c7f2f6..6a340318cc 100644
--- a/core/themes/claro/templates/system-themes-page.html.twig
+++ b/core/themes/claro/templates/system-themes-page.html.twig
@@ -22,6 +22,7 @@
  *     - notes: Identifies what context this theme is being used in, e.g.,
  *       default theme, admin theme.
  *     - incompatible: Text describing any compatibility issues.
+ *     - module_dependencies: A list of modules that this theme requires.
  *     - operations: A list of operation links, e.g., Settings, Enable, Disable,
  *       etc. these links should only be displayed if the theme is compatible.
  *     - title_id: The unique id of the theme label.
@@ -97,6 +98,9 @@
               </div>
 
               <div class="card__footer">
+                {% if theme.module_dependencies %}
+                  <div class="theme-info__requires">Requires: {{ theme.module_dependencies }}</div>
+                {% endif %}
                 {# Display operation links only if the theme is compatible. #}
                 {% if theme.incompatible %}
                   <small class="incompatible">{{ theme.incompatible }}</small>
diff --git a/core/themes/stable/templates/admin/system-themes-page.html.twig b/core/themes/stable/templates/admin/system-themes-page.html.twig
index 5a23f1a14c..a191606190 100644
--- a/core/themes/stable/templates/admin/system-themes-page.html.twig
+++ b/core/themes/stable/templates/admin/system-themes-page.html.twig
@@ -22,6 +22,7 @@
  *     - notes: Identifies what context this theme is being used in, e.g.,
  *       default theme, admin theme.
  *     - incompatible: Text describing any compatibility issues.
+ *     - module_dependencies: A list of modules that this theme requires.
  *     - operations: A list of operation links, e.g., Settings, Enable, Disable,
  *       etc. these links should only be displayed if the theme is compatible.
  *
@@ -60,6 +61,9 @@
               {%- endif -%}
             </h3>
             <div class="theme-info__description">{{ theme.description }}</div>
+            {% if theme.module_dependencies %}
+              <div class="theme-info__requires">Requires: {{ theme.module_dependencies }}</div>
+            {% endif %}
             {# Display operation links if the theme is compatible. #}
             {% if theme.incompatible %}
               <div class="incompatible">{{ theme.incompatible }}</div>