diff --git a/README.md b/README.md
index 51282a1..133ed43 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ Create a a Vagrantfile that looks like the following, ensure to add `config.env.
 ```ruby
 Vagrant.configure("2") do |config|
   config.env.enable # enable the plugin
-  config.vm.box = ENV['BOX_NAME']
+  config.vm.box = #{ENV['BOX_NAME']}
 end
 ```
 
diff --git a/example/Vagrantfile b/example/Vagrantfile
index fd9a73d..d2d2077 100644
--- a/example/Vagrantfile
+++ b/example/Vagrantfile
@@ -3,7 +3,7 @@
 
 Vagrant.configure(2) do |config|
   config.env.enable
-  config.vm.box = ENV['BOX_NAME']
+  config.vm.box = #{ENV['BOX_NAME']}
   config.vm.network "forwarded_port", guest: 80, host: 8080, auto_correct: true
 
   config.vm.provider "virtualbox" do |v|