diff --git a/charts/kube-prometheus-stack/templates/thanos-ruler/ruler.yaml b/charts/kube-prometheus-stack/templates/thanos-ruler/ruler.yaml
index 6079603c23c5..4a7d6b55daee 100644
--- a/charts/kube-prometheus-stack/templates/thanos-ruler/ruler.yaml
+++ b/charts/kube-prometheus-stack/templates/thanos-ruler/ruler.yaml
@@ -101,7 +101,7 @@ spec:
 {{- end }}
 {{- if .Values.thanosRuler.thanosRulerSpec.objectStorageConfig }}
   objectStorageConfig:
-    key: objectstore-configs.yaml
+    key: object-storage-configs.yaml
     name: {{ template "kube-prometheus-stack.thanosRuler.name" . }}
 {{- end }}
 {{- if .Values.thanosRuler.thanosRulerSpec.labels }}