diff --git a/plugins/commands/serve/command.rb b/plugins/commands/serve/command.rb
index 19777e225bc..aa9094c8997 100644
--- a/plugins/commands/serve/command.rb
+++ b/plugins/commands/serve/command.rb
@@ -21,7 +21,7 @@ module CommandServe
     # Simple constant aliases to reduce namespace typing
     SDK = Hashicorp::Vagrant::Sdk
     SRV = Hashicorp::Vagrant
-    Empty = Google::Protobuf::Empty
+    Empty = ::Google::Protobuf::Empty
 
     autoload :Broker, Vagrant.source_root.join("plugins/commands/serve/broker").to_s
     autoload :Client, Vagrant.source_root.join("plugins/commands/serve/client").to_s