diff --git a/src/Symfony/Component/Routing/Loader/AnnotationClassLoader.php b/src/Symfony/Component/Routing/Loader/AnnotationClassLoader.php
index b63dc5c85e665..fbf7b0105cd51 100644
--- a/src/Symfony/Component/Routing/Loader/AnnotationClassLoader.php
+++ b/src/Symfony/Component/Routing/Loader/AnnotationClassLoader.php
@@ -106,11 +106,14 @@ public function setRouteAnnotationClass(string $class)
      */
     public function load(mixed $class, string $type = null): RouteCollection
     {
-        if (!class_exists($class)) {
-            throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $class));
+        if (!$class instanceof \ReflectionClass) {
+            if (!class_exists($class)) {
+                throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $class));
+            }
+
+            $class = new \ReflectionClass($class);
         }
 
-        $class = new \ReflectionClass($class);
         if ($class->isAbstract()) {
             throw new \InvalidArgumentException(sprintf('Annotations from class "%s" cannot be read as it is abstract.', $class->getName()));
         }
@@ -227,7 +230,7 @@ protected function addRoute(RouteCollection $collection, object $annot, array $g
 
     public function supports(mixed $resource, string $type = null): bool
     {
-        return \is_string($resource) && preg_match('/^(?:\\\\?[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)+$/', $resource) && (!$type || \in_array($type, ['annotation', 'attribute'], true));
+        return ($resource instanceof \ReflectionClass || \is_string($resource) && preg_match('/^(?:\\\\?[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)+$/', $resource)) && (!$type || \in_array($type, ['annotation', 'attribute'], true));
     }
 
     public function setResolver(LoaderResolverInterface $resolver)
diff --git a/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php b/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
index 258673593625b..a27f744de348d 100644
--- a/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
+++ b/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
@@ -51,9 +51,9 @@ function (\SplFileInfo $current) {
                 continue;
             }
 
-            if ($class = $this->findClass($file)) {
-                $refl = new \ReflectionClass($class);
-                if ($refl->isAbstract()) {
+            if ($className = $this->findClass($file)) {
+                $class = new \ReflectionClass($className);
+                if ($class->isAbstract()) {
                     continue;
                 }
 
diff --git a/src/Symfony/Component/Routing/Loader/Psr4DirectoryLoader.php b/src/Symfony/Component/Routing/Loader/Psr4DirectoryLoader.php
index 9f262c006ffc2..433ce702afa8c 100644
--- a/src/Symfony/Component/Routing/Loader/Psr4DirectoryLoader.php
+++ b/src/Symfony/Component/Routing/Loader/Psr4DirectoryLoader.php
@@ -43,7 +43,7 @@ public function load(mixed $resource, string $type = null): ?RouteCollection
             return new RouteCollection();
         }
 
-        return $this->loadFromDirectory($path, trim($resource['namespace'], '\\'));
+        return $this->loadFromDirectory($path, trim($resource['namespace'], '\\'), $type);
     }
 
     public function supports(mixed $resource, string $type = null): bool
@@ -59,7 +59,7 @@ public function forDirectory(string $currentDirectory): static
         return $loader;
     }
 
-    private function loadFromDirectory(string $directory, string $psr4Prefix): RouteCollection
+    private function loadFromDirectory(string $directory, string $psr4Prefix, string $type): RouteCollection
     {
         $collection = new RouteCollection();
         $collection->addResource(new DirectoryResource($directory, '/\.php$/'));
@@ -79,7 +79,7 @@ function (\SplFileInfo $current) {
         /** @var \SplFileInfo $file */
         foreach ($files as $file) {
             if ($file->isDir()) {
-                $collection->addCollection($this->loadFromDirectory($file->getPathname(), $psr4Prefix.'\\'.$file->getFilename()));
+                $collection->addCollection($this->loadFromDirectory($file->getPathname(), $psr4Prefix.'\\'.$file->getFilename(), $type));
 
                 continue;
             }
@@ -87,7 +87,12 @@ function (\SplFileInfo $current) {
                 continue;
             }
 
-            $collection->addCollection($this->import($className, 'attribute'));
+            $class = new \ReflectionClass($className);
+            if ($class->isAbstract()) {
+                continue;
+            }
+
+            $collection->addCollection($this->import($class, $type));
         }
 
         return $collection;
diff --git a/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/IrrelevantClass.php b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/IrrelevantClass.php
new file mode 100644
index 0000000000000..ca3c1bcbddcaf
--- /dev/null
+++ b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/IrrelevantClass.php
@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace;
+
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * An irrelevant class.
+ *
+ * This fixture is not referenced anywhere. Its presence makes sure, classes without attributes are silently ignored
+ * when loading routes from a directory.
+ */
+final class IrrelevantClass
+{
+    public function irrelevantAction(): Response
+    {
+        return new Response(status: Response::HTTP_NO_CONTENT);
+    }
+}
diff --git a/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyAbstractController.php b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyAbstractController.php
new file mode 100644
index 0000000000000..30d8bbdb65bcc
--- /dev/null
+++ b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyAbstractController.php
@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace;
+
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Annotation\Route;
+
+abstract class MyAbstractController
+{
+    #[Route('/a/route/from/an/abstract/controller', name: 'from_abstract')]
+    public function someAction(): Response
+    {
+        return new Response(status: Response::HTTP_NO_CONTENT);
+    }
+}
diff --git a/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyChildController.php b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyChildController.php
new file mode 100644
index 0000000000000..a6d0333577079
--- /dev/null
+++ b/src/Symfony/Component/Routing/Tests/Fixtures/Psr4Controllers/SubNamespace/MyChildController.php
@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace;
+
+use Symfony\Component\Routing\Annotation\Route;
+
+#[Route('/my/child/controller', name: 'my_child_controller_')]
+final class MyChildController extends MyAbstractController
+{
+}
diff --git a/src/Symfony/Component/Routing/Tests/Loader/Psr4DirectoryLoaderTest.php b/src/Symfony/Component/Routing/Tests/Loader/Psr4DirectoryLoaderTest.php
index 541d352746c90..2bae59005fa60 100644
--- a/src/Symfony/Component/Routing/Tests/Loader/Psr4DirectoryLoaderTest.php
+++ b/src/Symfony/Component/Routing/Tests/Loader/Psr4DirectoryLoaderTest.php
@@ -21,6 +21,7 @@
 use Symfony\Component\Routing\RouteCollection;
 use Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\MyController;
 use Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace\EvenDeeperNamespace\MyOtherController;
+use Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace\MyChildController;
 use Symfony\Component\Routing\Tests\Fixtures\Psr4Controllers\SubNamespace\MyControllerWithATrait;
 
 class Psr4DirectoryLoaderTest extends TestCase
@@ -56,6 +57,14 @@ public function testTraitController()
         $this->assertSame(MyControllerWithATrait::class.'::someAction', $route->getDefault('_controller'));
     }
 
+    public function testAbstractController()
+    {
+        $route = $this->loadPsr4Controllers()->get('my_child_controller_from_abstract');
+
+        $this->assertSame('/my/child/controller/a/route/from/an/abstract/controller', $route->getPath());
+        $this->assertSame(MyChildController::class.'::someAction', $route->getDefault('_controller'));
+    }
+
     /**
      * @dataProvider provideNamespacesThatNeedTrimming
      */