diff --git a/defaults/main.yaml b/defaults/main.yaml
index 5d226dd..676dc4f 100644
--- a/defaults/main.yaml
+++ b/defaults/main.yaml
@@ -89,7 +89,7 @@ zuul_file_web_logging_conf_src: etc/zuul/web-logging.conf
 
 zuul_file_zuul_conf_dest: /etc/zuul/zuul.conf
 zuul_file_zuul_conf_group: "{{ zuul_user_group }}"
-zuul_file_zuul_conf_mode: 0644
+zuul_file_zuul_conf_mode: 0640
 zuul_file_zuul_conf_owner: "{{ zuul_user_name }}"
 zuul_file_zuul_conf_src: etc/zuul/zuul.conf