diff --git a/mypy_django_plugin/django/context.py b/mypy_django_plugin/django/context.py
index 347ec92ef..df69f95f2 100644
--- a/mypy_django_plugin/django/context.py
+++ b/mypy_django_plugin/django/context.py
@@ -369,6 +369,9 @@ def get_field_related_model_cls(self, field: Union["RelatedField[Any, Any]", For
         else:
             related_model_cls = field.field.model
 
+        if related_model_cls is None:
+            raise UnregisteredModelError
+
         if isinstance(related_model_cls, str):
             if related_model_cls == "self":  # type: ignore[unreachable]
                 # same model