diff --git a/tools/gce_setup/grpc_docker.sh b/tools/gce_setup/grpc_docker.sh
index 54cec2f144091331555b0593aab7a76968c2ef6c..117edd55ba0855f5bc22ec05252c313053fe2e82 100755
--- a/tools/gce_setup/grpc_docker.sh
+++ b/tools/gce_setup/grpc_docker.sh
@@ -994,7 +994,7 @@ grpc_cloud_prod_auth_compute_engine_creds_gen_ruby_cmd() {
   local gfe_flags=$(_grpc_prod_gfe_flags)
   local added_gfe_flags=$(_grpc_gce_test_flags)
   local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
-  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $added_gfe_flag $@'"
+  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $added_gfe_flags $@'"
   echo $the_cmd
 }