diff --git a/setup.sh b/setup.sh
index 2b45be3..ccaf518 100755
--- a/setup.sh
+++ b/setup.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 # Copyright 2019 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");