diff --git a/src/Symfony/Component/BrowserKit/Tests/ClientTest.php b/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
index ab6d118589..a21a9481a7 100644
--- a/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
+++ b/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
@@ -621,6 +621,9 @@ class ClientTest extends TestCase
         $this->assertEquals([], $client->getCookieJar()->all(), '->restart() clears the cookies');
     }
 
+    /**
+     * @runInSeparateProcess
+     */
     public function testInsulatedRequests()
     {
         $client = new TestClient();