diff --git a/apps/settings/composer/composer/autoload_classmap.php b/apps/settings/composer/composer/autoload_classmap.php
index 60717a4729449..ff402d11c7441 100644
--- a/apps/settings/composer/composer/autoload_classmap.php
+++ b/apps/settings/composer/composer/autoload_classmap.php
@@ -88,6 +88,7 @@
     'OCA\\Settings\\SetupChecks\\FileLocking' => $baseDir . '/../lib/SetupChecks/FileLocking.php',
     'OCA\\Settings\\SetupChecks\\ForwardedForHeaders' => $baseDir . '/../lib/SetupChecks/ForwardedForHeaders.php',
     'OCA\\Settings\\SetupChecks\\InternetConnectivity' => $baseDir . '/../lib/SetupChecks/InternetConnectivity.php',
+    'OCA\\Settings\\SetupChecks\\JavaScriptModules' => $baseDir . '/../lib/SetupChecks/JavaScriptModules.php',
     'OCA\\Settings\\SetupChecks\\LegacySSEKeyFormat' => $baseDir . '/../lib/SetupChecks/LegacySSEKeyFormat.php',
     'OCA\\Settings\\SetupChecks\\MaintenanceWindowStart' => $baseDir . '/../lib/SetupChecks/MaintenanceWindowStart.php',
     'OCA\\Settings\\SetupChecks\\MemcacheConfigured' => $baseDir . '/../lib/SetupChecks/MemcacheConfigured.php',
diff --git a/apps/settings/composer/composer/autoload_static.php b/apps/settings/composer/composer/autoload_static.php
index 7cd3892a6ec83..f94bb2e4a1e70 100644
--- a/apps/settings/composer/composer/autoload_static.php
+++ b/apps/settings/composer/composer/autoload_static.php
@@ -103,6 +103,7 @@ class ComposerStaticInitSettings
         'OCA\\Settings\\SetupChecks\\FileLocking' => __DIR__ . '/..' . '/../lib/SetupChecks/FileLocking.php',
         'OCA\\Settings\\SetupChecks\\ForwardedForHeaders' => __DIR__ . '/..' . '/../lib/SetupChecks/ForwardedForHeaders.php',
         'OCA\\Settings\\SetupChecks\\InternetConnectivity' => __DIR__ . '/..' . '/../lib/SetupChecks/InternetConnectivity.php',
+        'OCA\\Settings\\SetupChecks\\JavaScriptModules' => __DIR__ . '/..' . '/../lib/SetupChecks/JavaScriptModules.php',
         'OCA\\Settings\\SetupChecks\\LegacySSEKeyFormat' => __DIR__ . '/..' . '/../lib/SetupChecks/LegacySSEKeyFormat.php',
         'OCA\\Settings\\SetupChecks\\MaintenanceWindowStart' => __DIR__ . '/..' . '/../lib/SetupChecks/MaintenanceWindowStart.php',
         'OCA\\Settings\\SetupChecks\\MemcacheConfigured' => __DIR__ . '/..' . '/../lib/SetupChecks/MemcacheConfigured.php',
diff --git a/apps/settings/js/esm-test.mjs b/apps/settings/js/esm-test.mjs
new file mode 100644
index 0000000000000..597a0312f7f2a
--- /dev/null
+++ b/apps/settings/js/esm-test.mjs
@@ -0,0 +1,5 @@
+/**
+ * This is a dummy file for testing webserver support of JavaScript modules.
+ */
+
+export default 'Hello'
diff --git a/apps/settings/lib/AppInfo/Application.php b/apps/settings/lib/AppInfo/Application.php
index f3e2343e04886..ce619478bd43a 100644
--- a/apps/settings/lib/AppInfo/Application.php
+++ b/apps/settings/lib/AppInfo/Application.php
@@ -60,6 +60,7 @@
 use OCA\Settings\SetupChecks\FileLocking;
 use OCA\Settings\SetupChecks\ForwardedForHeaders;
 use OCA\Settings\SetupChecks\InternetConnectivity;
+use OCA\Settings\SetupChecks\JavaScriptModules;
 use OCA\Settings\SetupChecks\LegacySSEKeyFormat;
 use OCA\Settings\SetupChecks\MaintenanceWindowStart;
 use OCA\Settings\SetupChecks\MemcacheConfigured;
@@ -177,6 +178,7 @@ public function register(IRegistrationContext $context): void {
 		$context->registerSetupCheck(FileLocking::class);
 		$context->registerSetupCheck(ForwardedForHeaders::class);
 		$context->registerSetupCheck(InternetConnectivity::class);
+		$context->registerSetupCheck(JavaScriptModules::class);
 		$context->registerSetupCheck(LegacySSEKeyFormat::class);
 		$context->registerSetupCheck(MaintenanceWindowStart::class);
 		$context->registerSetupCheck(MemcacheConfigured::class);
diff --git a/apps/settings/lib/SetupChecks/JavaScriptModules.php b/apps/settings/lib/SetupChecks/JavaScriptModules.php
new file mode 100644
index 0000000000000..151e04ecf2bf4
--- /dev/null
+++ b/apps/settings/lib/SetupChecks/JavaScriptModules.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2023 Ferdinand Thiessen <opensource@fthiessen.de>
+ *
+ * @author Ferdinand Thiessen <opensource@fthiessen.de>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\Settings\SetupChecks;
+
+use OCP\Http\Client\IClientService;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\SetupCheck\ISetupCheck;
+use OCP\SetupCheck\SetupResult;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Checks if the webserver serves '.mjs' files using the correct MIME type
+ */
+class JavaScriptModules implements ISetupCheck {
+	public function __construct(
+		private IL10N $l10n,
+		private IConfig $config,
+		private IURLGenerator $urlGenerator,
+		private IClientService $clientService,
+		private LoggerInterface $logger,
+	) {
+	}
+
+	public function getCategory(): string {
+		return 'network';
+	}
+
+	public function getName(): string {
+		return $this->l10n->t('JavaScript modules support');
+	}
+
+	public function run(): SetupResult {
+		$testFile = $this->urlGenerator->linkTo('settings', 'js/esm-test.mjs');
+		$testURLs = array_merge(
+			[$this->urlGenerator->getAbsoluteURL($testFile)],
+			array_map(fn (string $host): string => $host . $testFile, $this->config->getSystemValue('trusted_domains', []))
+		);
+
+		foreach ($testURLs as $testURL) {
+			try {
+				$client = $this->clientService->newClient();
+				$response = $client->head($testURL, ['connect_timeout' => 10]);
+				if (preg_match('/(text|application)\/javascript/i', $response->getHeader('Content-Type'))) {
+					return SetupResult::success();
+				}
+			} catch (\Throwable $e) {
+				$this->logger->debug('Can not connect to local server for checking JavaScript modules support', ['exception' => $e, 'url' => $testURL]);
+			}
+		}
+		return SetupResult::error($this->l10n->t('Your webserver does not serve `.mjs` files using the JavaScript MIME type. This will break some apps by preventing browsers from executing the JavaScript files. You should configure your webserver to serve `.mjs` files with either the `text/javascript` or `application/javascript` MIME type.'));
+	}
+}