diff --git a/airflow-core/src/airflow/models/dagrun.py b/airflow-core/src/airflow/models/dagrun.py
index 25f6397c074ec..36ef372e39aa2 100644
--- a/airflow-core/src/airflow/models/dagrun.py
+++ b/airflow-core/src/airflow/models/dagrun.py
@@ -836,7 +836,7 @@ def fetch_task_instances(
         dag_id: str | None = None,
         run_id: str | None = None,
         task_ids: list[str] | None = None,
-        state: Iterable[TaskInstanceState | None] | None = None,
+        state: TaskInstanceState | Iterable[TaskInstanceState | None] | None = None,
         *,
         session: Session = NEW_SESSION,
     ) -> list[TI]:
@@ -917,7 +917,7 @@ def _check_last_n_dagruns_failed(self, dag_id, max_consecutive_failed_dag_runs,
     @provide_session
     def get_task_instances(
         self,
-        state: Iterable[TaskInstanceState | None] | None = None,
+        state: TaskInstanceState | Iterable[TaskInstanceState | None] | None = None,
         *,
         session: Session = NEW_SESSION,
     ) -> list[TI]: