diff --git a/helpdesk/views/staff.py b/helpdesk/views/staff.py
index f98a4934..b6ee8da0 100644
--- a/helpdesk/views/staff.py
+++ b/helpdesk/views/staff.py
@@ -485,7 +485,7 @@ def view_ticket(request, ticket_id):
             "checklist_form": checklist_form,
             "customfields_form": customfields_form,
             "assignable_users": get_assignable_users(
-                settings.HELPDESK_STAFF_ONLY_TICKET_OWNERS
+                bool(getattr(settings, "HELPDESK_STAFF_ONLY_TICKET_OWNERS", False))
             ),
             **extra_context_kwargs,
         },