diff --git a/syntax/ats.vim b/syntax/ats.vim
index 4f5bfa8..2a7e507 100644
--- a/syntax/ats.vim
+++ b/syntax/ats.vim
@@ -82,7 +82,7 @@ syn keyword atsExternal extern implement primplmnt
 syn keyword atsKeyword symintr overload with
 syn keyword atsKeyword prval praxi datasort
 
-syn keyword atsSorts bool char int absprop prop type view viewtype nat absvtype absviewtype
+syn keyword atsSorts bool char int absprop prop type view viewtype nat absvtype absviewtype vtype
 
 syn keyword atsTypes string float double void