diff --git a/airflow/api_connexion/openapi/v1.yaml b/airflow/api_connexion/openapi/v1.yaml
index fc71fbb7f5e3d..ab982b53d588a 100644
--- a/airflow/api_connexion/openapi/v1.yaml
+++ b/airflow/api_connexion/openapi/v1.yaml
@@ -3634,6 +3634,7 @@ components:
       description: |
         Schedule interval. Defines how often DAG runs, this object gets added to your latest task instance's
         execution_date to figure out the next schedule.
+      nullable: true
       readOnly: true
       anyOf:
         - $ref: '#/components/schemas/TimeDelta'