diff --git a/collects/typed-scheme/scribblings/ts-reference.scrbl b/collects/typed-scheme/scribblings/ts-reference.scrbl
index 196e9ebef8..af6677c826 100644
--- a/collects/typed-scheme/scribblings/ts-reference.scrbl
+++ b/collects/typed-scheme/scribblings/ts-reference.scrbl
@@ -84,6 +84,7 @@ default in Racket.
 @defidform[PRegexp]
 @defidform[Bytes]
 @defidform[Namespace]
+@defidform[Null]
 @defidform[EOF]
 @defidform[Continuation-Mark-Set]
 @defidform[Char]