diff --git a/backend/tests/Feature/Auth/LogoutEndpointTest.php b/backend/tests/Feature/Auth/LogoutEndpointTest.php
new file mode 100644
index 0000000..3986cb9
--- /dev/null
+++ b/backend/tests/Feature/Auth/LogoutEndpointTest.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace Tests\Feature\Auth;
+
+use App\Auth\CreateSessionDto;
+use App\Auth\SessionRepository;
+use App\Http\Middleware\AuthMiddleware;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\CreateUserDto;
+use App\User\UserRepository;
+use DateTimeImmutable;
+use DateTimeZone;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class LogoutEndpointTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_logout_deletes_session_and_clears_cookie(): void
+    {
+        $now = new DateTimeImmutable(
+            '2026-07-31T12:00:00',
+            new DateTimeZone('UTC'),
+        );
+        $user = app(UserRepository::class)->create(new CreateUserDto(
+            email: new EmailAddress('user@example.com'),
+            passwordHash: 'hashed-password',
+        ));
+        app(SessionRepository::class)->create(new CreateSessionDto(
+            token: 'session-token',
+            user: $user,
+            createdAt: $now,
+            expiresAt: $now->modify('+7 days'),
+        ));
+
+        $response = $this->withCredentials()
+            ->withUnencryptedCookie(
+                AuthMiddleware::COOKIE_NAME,
+                'session-token',
+            )->postJson('/api/logout');
+
+        $response->assertNoContent();
+        $response->assertCookieExpired(AuthMiddleware::COOKIE_NAME);
+        $this->assertNull(
+            app(SessionRepository::class)->findByToken('session-token'),
+        );
+    }
+
+    public function test_logout_rejects_a_request_without_a_cookie(): void
+    {
+        $response = $this->postJson('/api/logout');
+
+        $response
+            ->assertStatus(401)
+            ->assertExactJson(['error' => 'unauthenticated']);
+    }
+}
diff --git a/backend/tests/Unit/Auth/UseCases/LogoutTest.php b/backend/tests/Unit/Auth/UseCases/LogoutTest.php
new file mode 100644
index 0000000..5accde6
--- /dev/null
+++ b/backend/tests/Unit/Auth/UseCases/LogoutTest.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace Tests\Unit\Auth\UseCases;
+
+use App\Auth\CreateSessionDto;
+use App\Auth\UseCases\Logout\Logout;
+use App\Shared\ValueObject\EmailAddress;
+use App\User\User;
+use DateTimeImmutable;
+use DateTimeZone;
+use PHPUnit\Framework\TestCase;
+use Tests\Fakes\FakeSessionRepository;
+
+class LogoutTest extends TestCase
+{
+    private FakeSessionRepository $sessionRepository;
+
+    private Logout $useCase;
+
+    protected function setUp(): void
+    {
+        $this->sessionRepository = new FakeSessionRepository;
+        $this->useCase = new Logout($this->sessionRepository);
+    }
+
+    public function test_existing_token_session_is_removed(): void
+    {
+        $now = new DateTimeImmutable(
+            '2026-07-31T12:00:00',
+            new DateTimeZone('UTC'),
+        );
+        $this->sessionRepository->create(new CreateSessionDto(
+            token: 'session-token',
+            user: new User(
+                id: 7,
+                email: new EmailAddress('user@example.com'),
+                passwordHash: 'hashed-password',
+            ),
+            createdAt: $now,
+            expiresAt: $now->modify('+7 days'),
+        ));
+
+        $this->useCase->execute('session-token');
+
+        $this->assertNull(
+            $this->sessionRepository->findByToken('session-token'),
+        );
+    }
+
+    public function test_unknown_token_does_not_throw(): void
+    {
+        $this->useCase->execute('unknown-token');
+
+        $this->assertNull(
+            $this->sessionRepository->findByToken('unknown-token'),
+        );
+    }
+}
diff --git a/backend/tests/Unit/Http/Controllers/AuthControllerTest.php b/backend/tests/Unit/Http/Controllers/AuthControllerTest.php
index cded75c..5372272 100644
--- a/backend/tests/Unit/Http/Controllers/AuthControllerTest.php
+++ b/backend/tests/Unit/Http/Controllers/AuthControllerTest.php
@@ -4,6 +4,7 @@ namespace Tests\Unit\Http\Controllers;
 
 use App\Auth\UseCases\AuthenticateUser\AuthenticateUser;
 use App\Auth\UseCases\CreateSession\CreateSession;
+use App\Auth\UseCases\Logout\Logout;
 use App\Http\Controllers\AuthController;
 use App\Http\Middleware\AuthMiddleware;
 use App\Shared\ValueObject\EmailAddress;
@@ -45,9 +46,11 @@ class AuthControllerTest extends TestCase
                 new DateTimeZone('UTC'),
             )),
         );
+        $logout = new Logout($this->sessionRepository);
         $this->controller = new AuthController(
             $authenticateUser,
             $createSession,
+            $logout,
         );
     }
 
@@ -117,6 +120,37 @@ class AuthControllerTest extends TestCase
         );
     }
 
+    public function test_logout_deletes_session_and_clears_cookie(): void
+    {
+        $this->createUser('correct-password');
+        $this->controller->login(new Request([
+            'email' => 'user@example.com',
+            'password' => 'correct-password',
+        ]));
+        $request = new Request;
+        $request->cookies->set(
+            AuthMiddleware::COOKIE_NAME,
+            'session-token',
+        );
+
+        $response = $this->controller->logout($request);
+
+        $this->assertSame(204, $response->getStatusCode());
+        $this->assertNull(
+            $this->sessionRepository->findByToken('session-token'),
+        );
+        $cookies = $response->headers->getCookies();
+        $this->assertCount(1, $cookies);
+        $this->assertSame(
+            AuthMiddleware::COOKIE_NAME,
+            $cookies[0]->getName(),
+        );
+        $this->assertSame('', $cookies[0]->getValue());
+        $this->assertSame(1, $cookies[0]->getExpiresTime());
+        $this->assertTrue($cookies[0]->isHttpOnly());
+        $this->assertSame('lax', $cookies[0]->getSameSite());
+    }
+
     private function createUser(string $password): void
     {
         $this->userRepository->create(new CreateUserDto(