diff --git a/src/RunServerListener.php b/src/RunServerListener.php
index f5d6dfa..abf3f5c 100644
--- a/src/RunServerListener.php
+++ b/src/RunServerListener.php
@@ -36,6 +36,7 @@ class RunServerListener implements EventSubscriberInterface
     private static int $port = 0;
     private ?int $verbose = null;
     private string $rootDir;
+    private string $runAs = '';
     private static self $instance;
 
     public function __construct(?int $verbose, string $rootDir, string $host)
@@ -79,6 +80,10 @@ public function start(): void
 
         $cmd = 'php -S ' . self::$host .':' . self::$port . ' -t ' . $script;
 
+        if ($this->runAs) {
+            $cmd = 'runuser -u ' . $this->runAs . ' -- ' . $cmd;
+        }
+
         if (is_numeric($this->verbose)) {
             $verbose = '';
         } else {
@@ -195,8 +200,10 @@ public function getPort()
      * Let the OS find an open port for you.
      *
      * @return int
+     *
+     * @psalm-return int<1, max>
      */
-    private function findOpenPort()
+    private function findOpenPort(): int
     {
         $sock = socket_create(AF_INET, SOCK_STREAM, 0);
 
diff --git a/src/Server.php b/src/Server.php
index d977eaa..be19fa1 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -72,6 +72,10 @@ public function configure(ArrayNodeDefinition $builder): void
                     ->info('Host domain or IP')
                     ->defaultValue('localhost')
                 ->end()
+                ->scalarNode('runAs')
+                    ->info('The username to be used to run the built-in server')
+                    ->defaultValue('')
+                ->end()
             ->end()
         ;
     }
@@ -88,9 +92,10 @@ public function load(ContainerBuilder $container, array $config): void
             }
         }
         $host = $this->getHost($config);
+        $runAs = $this->getRunAs($config);
         $definition = (new Definition('PhpBuiltin\RunServerListener'))
             ->addTag('event_dispatcher.subscriber')
-            ->setArguments([$verbose, $rootDir, $host])
+            ->setArguments([$verbose, $rootDir, $host, $runAs])
         ;
 
         $container->setDefinition(self::ID . '.listener', $definition);
@@ -105,6 +110,15 @@ private function getHost(array $config): string
         return (string) $host;
     }
 
+    private function getRunAs(array $config): string
+    {
+        $runAs = getenv('BEHAT_RUN_AS');
+        if ($runAs === false) {
+            $runAs = $config['runAs'];
+        }
+        return (string) $runAs;
+    }
+
     private function getRootDir(array $config): string
     {
         $rootDir = getenv('BEHAT_ROOT_DIR');