diff --git a/migrations_lockfile.txt b/migrations_lockfile.txt
index 7e5efc99689f99..33c5203ba84c10 100644
--- a/migrations_lockfile.txt
+++ b/migrations_lockfile.txt
@@ -17,7 +17,7 @@ hybridcloud: 0024_add_project_distribution_scope
 
 insights: 0002_backfill_team_starred
 
-monitors: 0012_remove_monitor_is_muted_field
+monitors: 0013_fix_monitorincident_checkin_cascade
 
 nodestore: 0001_squashed_0002_nodestore_no_dictfield
 
diff --git a/src/sentry/monitors/migrations/0013_fix_monitorincident_checkin_cascade.py b/src/sentry/monitors/migrations/0013_fix_monitorincident_checkin_cascade.py
new file mode 100644
index 00000000000000..39e93ed22d1f24
--- /dev/null
+++ b/src/sentry/monitors/migrations/0013_fix_monitorincident_checkin_cascade.py
@@ -0,0 +1,50 @@
+# Generated by Django 5.2.8 on 2025-11-19 23:35
+
+import django.db.models.deletion
+from django.db import migrations
+
+import sentry.db.models.fields.foreignkey
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("monitors", "0012_remove_monitor_is_muted_field"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="monitorincident",
+            name="starting_checkin",
+            field=sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="created_incidents",
+                to="monitors.monitorcheckin",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="monitorincident",
+            name="resolving_checkin",
+            field=sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="resolved_incidents",
+                to="monitors.monitorcheckin",
+            ),
+        ),
+    ]