diff --git a/doc/maintainers.rdoc b/doc/maintainers.rdoc
index cf13ad6588..32d6296830 100644
--- a/doc/maintainers.rdoc
+++ b/doc/maintainers.rdoc
@@ -52,8 +52,6 @@ Zachary Scott (zzak)
   Masatoshi SEKI (seki)
 [lib/debug.rb]
   _unmaintained_
-[lib/delegate.rb]
-  _unmaintained_
 [lib/erb.rb]
   Masatoshi SEKI (seki), Takashi Kokubun (k0kubun)
 [lib/find.rb]
@@ -170,6 +168,10 @@ Zachary Scott (zzak)
   Kenta Murata (mrkn), Kouhei Sutou (kou)
   https://github.com/ruby/csv
   https://rubygems.org/gems/csv
+[lib/delegate.rb]
+  _unmaintained_
+  https://github.com/ruby/delegate
+  https://rubygems.org/gems/delegate
 [lib/e2mmap.rb]
   Keiju ISHITSUKA (keiju)
   https://rubygems.org/gems/e2mmap
diff --git a/doc/standard_library.rdoc b/doc/standard_library.rdoc
index a18d6ea001..3e4c7de7f7 100644
--- a/doc/standard_library.rdoc
+++ b/doc/standard_library.rdoc
@@ -13,7 +13,6 @@ Base64:: Support for encoding and decoding binary data using a Base64 representa
 Benchmark:: Provides methods to measure and report the time used to execute code
 CGI:: Support for the Common Gateway Interface protocol
 DEBUGGER__:: Debugging functionality for Ruby
-Delegator:: Provides three abilities to delegate method calls to an object
 DRb:: Distributed object system for Ruby
 English.rb:: Require 'English.rb' to reference global variables with less cryptic names
 ERB:: An easy to use but powerful templating system for Ruby
@@ -69,6 +68,7 @@ WIN32OLE:: Provides an interface for OLE Automation in Ruby
 
 Bundler:: Manage your Ruby application's gem dependencies
 CSV:: Provides an interface to read and write CSV files and data
+Delegator:: Provides three abilities to delegate method calls to an object
 E2MM:: Module for defining custom exceptions with specific messages
 FileUtils:: Several file utility methods for copying, moving, removing, etc
 Forwardable:: Provides delegation of specified methods to a designated object
diff --git a/lib/delegate/delegate.gemspec b/lib/delegate/delegate.gemspec
new file mode 100644
index 0000000000..e51b50a98f
--- /dev/null
+++ b/lib/delegate/delegate.gemspec
@@ -0,0 +1,27 @@
+begin
+  require_relative "lib/delegate/version"
+rescue LoadError # Fallback to load version file in ruby core repository
+  require_relative "version"
+end
+
+Gem::Specification.new do |spec|
+  spec.name          = "delegate"
+  spec.version       = Delegator::VERSION
+  spec.authors       = ["Yukihiro Matsumoto"]
+  spec.email         = ["matz@ruby-lang.org"]
+
+  spec.summary       = %q{Provides three abilities to delegate method calls to an object.}
+  spec.description   = %q{Provides three abilities to delegate method calls to an object.}
+  spec.homepage      = "https://github.com/ruby/delegate"
+  spec.license       = "BSD-2-Clause"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+end
diff --git a/lib/delegate/version.rb b/lib/delegate/version.rb
new file mode 100644
index 0000000000..456e8f772c
--- /dev/null
+++ b/lib/delegate/version.rb
@@ -0,0 +1,3 @@
+class Delegator
+  VERSION = "0.1.0"
+end
diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 3c52a72640..31dd664cdc 100644
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -37,6 +37,7 @@
 # * https://github.com/ruby/open3
 # * https://github.com/ruby/getoptlong
 # * https://github.com/ruby/pstore
+# * https://github.com/ruby/delegate
 #
 
 require 'fileutils'
@@ -81,6 +82,7 @@ $repositories = {
   open3: "ruby/open3",
   getoptlong: "ruby/getoptlong",
   pstore: "ruby/pstore",
+  delegate: "ruby/delegate",
 }
 
 def sync_default_gems(gem)