diff --git a/doc/maintainers.md b/doc/maintainers.md
index 2a6a0545ef..5e117196c7 100644
--- a/doc/maintainers.md
+++ b/doc/maintainers.md
@@ -350,11 +350,6 @@ have commit right, others don't.
 * https://github.com/flori/json
 * https://rubygems.org/gems/json
 
-#### ext/nkf
-* NARUSE, Yui (naruse)
-* https://github.com/ruby/nkf
-* https://rubygems.org/gems/nkf
-
 #### ext/openssl
 * Kazuki Yamaguchi (rhe)
 * https://github.com/ruby/openssl
@@ -472,6 +467,9 @@ have commit right, others don't.
 #### drb
 * https://github.com/ruby/drb
 
+#### nkf
+* https://github.com/ruby/nkf
+
 ## Platform Maintainers
 ### mswin64 (Microsoft Windows)
 * NAKAMURA Usaku (usa)
diff --git a/doc/standard_library.rdoc b/doc/standard_library.rdoc
index 4833defe45..c099ea5c71 100644
--- a/doc/standard_library.rdoc
+++ b/doc/standard_library.rdoc
@@ -85,7 +85,6 @@ Fcntl:: Loads constants defined in the OS fcntl.h C header file
 Fiddle:: A libffi wrapper for Ruby
 IO:: Extensions for Ruby IO class, including #wait, #nonblock and ::console
 JSON:: Implements Javascript Object Notation for Ruby
-NKF:: Ruby extension for Network Kanji Filter
 OpenSSL:: Provides SSL, TLS and general purpose cryptography for Ruby
 Pathname:: Representation of the name of a file or directory on the filesystem
 Psych:: A YAML parser and emitter for Ruby
@@ -130,3 +129,4 @@ Abbrev:: Calculates a set of unique abbreviations for a given set of strings
 resolv-replace.rb:: Replace Socket DNS with Resolv
 Rinda:: The Linda distributed computing paradigm in Ruby
 DRb:: Distributed object system for Ruby
+NKF:: Ruby extension for Network Kanji Filter