diff --git a/apps/emqx/.gitignore b/apps/emqx/.gitignore
new file mode 100644
index 000000000..e33ea388e
--- /dev/null
+++ b/apps/emqx/.gitignore
@@ -0,0 +1,2 @@
+# See: emqx_common_test_helpers:copy_acl_conf/0
+etc/acl.conf