diff --git a/validation/custom_constraint.rst b/validation/custom_constraint.rst
index f4f81294c38..fc6a0785667 100644
--- a/validation/custom_constraint.rst
+++ b/validation/custom_constraint.rst
@@ -60,6 +60,7 @@ The validator class is also simple, and only has one required method ``validate(
     use Symfony\Component\Validator\Constraint;
     use Symfony\Component\Validator\ConstraintValidator;
     use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+    use Symfony\Component\Validator\Exception\UnexpectedValueException;
 
     class ContainsAlphanumericValidator extends ConstraintValidator
     {