diff --git a/reference/constraints/Callback.rst b/reference/constraints/Callback.rst
index eea2f4f0b76..2a858f0656b 100644
--- a/reference/constraints/Callback.rst
+++ b/reference/constraints/Callback.rst
@@ -59,7 +59,7 @@ Configuration
         # src/AppBundle/Resources/config/validation.yml
         AppBundle\Entity\Author:
             constraints:
-                - Callback: [validate]
+                - Callback: validate
 
     .. code-block:: xml