diff --git a/core/lib/Drupal/Core/Extension/ThemeInstaller.php b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
index c6d6106..70a9eac 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstaller.php
@@ -221,7 +221,7 @@ public function uninstall(array $theme_list) {
     $list = $this->themeHandler->listInfo();
     foreach ($theme_list as $key) {
       if (!isset($list[$key])) {
-        throw new UninstalledExtensionException("Unknown theme: $key.");
+        throw new UnknownExtensionException("Unknown theme: $key.");
       }
       if ($key === $theme_config->get('default')) {
         throw new \InvalidArgumentException("The current default theme $key cannot be uninstalled.");
diff --git a/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php b/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
index a37c432..ff9b95e 100644
--- a/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
+++ b/core/lib/Drupal/Core/Extension/ThemeInstallerInterface.php
@@ -37,9 +37,12 @@ public function install(array $theme_list, $install_dependencies = TRUE);
    * @param array $theme_list
    *   The themes to uninstall.
    *
-   * @throws \Drupal\Core\Extension\UninstalledExtensionException
+   * @throws \Drupal\Core\Extension\UnknownExtensionException
    *   Thrown when trying to uninstall a theme that was not installed.
    *
+   * @throws \InvalidArgumentException
+   *   Thrown when trying to uninstall the default theme or the admin theme.
+   *
    * @see hook_themes_uninstalled()
    */
   public function uninstall(array $theme_list);
diff --git a/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php b/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
index 61f6475..795a51d 100644
--- a/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Theme/ThemeInstallerTest.php
@@ -4,6 +4,7 @@
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\Extension\ExtensionNameLengthException;
+use Drupal\Core\Extension\UnknownExtensionException;
 use Drupal\KernelTests\KernelTestBase;
 
 /**
@@ -110,11 +111,11 @@ public function testInstallNonExisting() {
     $this->assertFalse(array_keys($themes));
 
     try {
-      $message = 'ThemeHandler::install() throws InvalidArgumentException upon installing a non-existing theme.';
+      $message = 'ThemeHandler::install() throws UnknownExtensionException upon installing a non-existing theme.';
       $this->themeInstaller()->install([$name]);
       $this->fail($message);
     }
-    catch (\InvalidArgumentException $e) {
+    catch (UnknownExtensionException $e) {
       $this->pass(get_class($e) . ': ' . $e->getMessage());
     }
 
@@ -247,11 +248,11 @@ public function testUninstallNonExisting() {
     $this->assertFalse(array_keys($themes));
 
     try {
-      $message = 'ThemeHandler::uninstall() throws InvalidArgumentException upon uninstalling a non-existing theme.';
+      $message = 'ThemeHandler::uninstall() throws UnknownExtensionException upon uninstalling a non-existing theme.';
       $this->themeInstaller()->uninstall([$name]);
       $this->fail($message);
     }
-    catch (\InvalidArgumentException $e) {
+    catch (UnknownExtensionException $e) {
       $this->pass(get_class($e) . ': ' . $e->getMessage());
     }
 
@@ -291,11 +292,11 @@ public function testUninstallNotInstalled() {
     $name = 'test_basetheme';
 
     try {
-      $message = 'ThemeHandler::uninstall() throws InvalidArgumentException upon uninstalling a theme that is not installed.';
+      $message = 'ThemeHandler::uninstall() throws UnknownExtensionException upon uninstalling a theme that is not installed.';
       $this->themeInstaller()->uninstall([$name]);
       $this->fail($message);
     }
-    catch (\InvalidArgumentException $e) {
+    catch (UnknownExtensionException $e) {
       $this->pass(get_class($e) . ': ' . $e->getMessage());
     }
   }