diff --git a/charts/kube-prometheus-stack/templates/alertmanager/networkpolicy.yaml b/charts/kube-prometheus-stack/templates/alertmanager/networkpolicy.yaml
index d2dbc8ca0915..b3ee10ecbef4 100644
--- a/charts/kube-prometheus-stack/templates/alertmanager/networkpolicy.yaml
+++ b/charts/kube-prometheus-stack/templates/alertmanager/networkpolicy.yaml
@@ -38,6 +38,8 @@ spec:
       ports:
         - port: {{ .Values.alertmanager.service.port }}
           protocol: TCP
+        - port: 8080
+          protocol: TCP
     {{- end }}
     {{- if and (.Values.alertmanager.networkPolicy.enableClusterRules) (.Values.alertmanager.service.clusterPort) }}
     # Allow ingress from other Alertmanager pods (for clustering)