diff --git a/aws-iam-role-s3-readonly/main.tf b/aws-iam-role-s3-readonly/main.tf
index 5922b3f9..8e182b64 100644
--- a/aws-iam-role-s3-readonly/main.tf
+++ b/aws-iam-role-s3-readonly/main.tf
@@ -52,7 +52,7 @@ data "aws_iam_policy_document" "s3-bucket-readonly" {
     actions = [
       "s3:ListAllMyBuckets"
     ]
-    resources = toset(formatlist("arn:aws:s3:::%s", var.s3_bucket_names), formatlist("arn:aws:s3:::%s/*", var.s3_bucket_names))
+    resources = toset(concat(formatlist("arn:aws:s3:::%s", var.s3_bucket_names), formatlist("arn:aws:s3:::%s/*", var.s3_bucket_names)))
   }
 }