diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9311a63..380561f3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Prevent additional polling on Incidents if the previous request didn't complete
   ([#3205](https://github.com/grafana/oncall/pull/3205))
 - Order results from `GET /teams` internal API endpoint by ascending name by @joeyorlando ([#3220](https://github.com/grafana/oncall/pull/3220))
+- Order alert groups internal API endpoint by descending started_at by @mderynck ([#3240](https://github.com/grafana/oncall/pull/3240))
 
 ### Fixed
 
diff --git a/engine/apps/api/views/alert_group.py b/engine/apps/api/views/alert_group.py
index 97ef641e..f1db153a 100644
--- a/engine/apps/api/views/alert_group.py
+++ b/engine/apps/api/views/alert_group.py
@@ -423,7 +423,7 @@ class AlertGroupView(
 
         # enrich alert groups with select_related and prefetch_related
         alert_group_pks = [alert_group.pk for alert_group in alert_groups]
-        queryset = AlertGroup.objects.filter(pk__in=alert_group_pks).order_by("-pk")
+        queryset = AlertGroup.objects.filter(pk__in=alert_group_pks).order_by("-started_at")
 
         queryset = self.get_serializer_class().setup_eager_loading(queryset)
         alert_groups = list(queryset)