diff --git a/core/models.py b/core/models.py
index bdb8b31f..4eb241e3 100644
--- a/core/models.py
+++ b/core/models.py
@@ -866,7 +866,7 @@ class OrderProduct(ExportModelOperationsMixin("order_product"), NiceModel):
     )
 
     def __str__(self) -> str:
-        return f"{self.product.name} for ({self.order.user.email})"
+        return f"{self.product.name} for ({self.order.user.email if self.order.user else 'unregistered user'})"
 
     class Meta:
         verbose_name = _("order product")