diff --git a/collects/parser-tools/parser-tools.scrbl b/collects/parser-tools/parser-tools.scrbl
index 90debe4624..5f2a43a308 100644
--- a/collects/parser-tools/parser-tools.scrbl
+++ b/collects/parser-tools/parser-tools.scrbl
@@ -22,6 +22,10 @@ style lexer and parser generators.
 
 @section{Lexers}
 
+@section-index["lex"]
+@section-index["scanning"]
+@section-index["scanner"]
+
 @defmodule[parser-tools/lex]
 
 @; ----------------------------------------
@@ -484,6 +488,8 @@ the right choice when using @scheme[lexer] in other situations.
 
 @section{Parsers}
 
+@section-index["yacc"]
+
 @defmodule[parser-tools/yacc]
 
 @defform/subs[#:literals (grammar tokens start end precs src-pos