diff --git a/plugins/vagrant/_vagrant b/plugins/vagrant/_vagrant
index 3e16dbebf..e88835506 100644
--- a/plugins/vagrant/_vagrant
+++ b/plugins/vagrant/_vagrant
@@ -69,7 +69,7 @@ __box_list ()
 
 __vm_list ()
 {
-    _wanted application expl 'command' compadd $(command grep "${VAGRANT_CWD:-.}/Vagrantfile" -oe '^[^#]*\.vm\.define *[:"]\([a-zA-Z0-9_-]\+\)' 2>/dev/null | awk '{print substr($2, 2)}')
+    _wanted application expl 'command' compadd $(command grep "${VAGRANT_CWD:-.}/Vagrantfile" -oe '^[^#]*\.vm\.define *[:"]\([a-zA-Z0-9\._-]\+\)' 2>/dev/null | awk '{print substr($2, 2)}')
     _wanted application expl 'command' compadd $(command ls "${VAGRANT_CWD:-.}/.vagrant/machines/" 2>/dev/null)
 }