diff --git a/doc/maintainers.rdoc b/doc/maintainers.rdoc
index 087feb5134..05049e6a49 100644
--- a/doc/maintainers.rdoc
+++ b/doc/maintainers.rdoc
@@ -67,8 +67,6 @@ Zachary Scott (zzak)
   Akinori MUSHA (knu)
 [lib/time.rb]
   Tanaka Akira (akr)
-[lib/tsort.rb]
-  Tanaka Akira (akr)
 [lib/un.rb]
   WATANABE Hirofumi (eban)
 [lib/unicode_normalize.rb, lib/unicode_normalize/*]
@@ -255,6 +253,9 @@ Zachary Scott (zzak)
 [lib/tracer.rb]
   Keiju ISHITSUKA (keiju)
   https://github.com/ruby/tracer
+[lib/tsort.rb]
+  Tanaka Akira (akr)
+  https://github.com/ruby/tsort
 [lib/uri.rb, lib/uri/*]
   YAMADA, Akira (akira)
   https://github.com/ruby/uri
diff --git a/doc/standard_library.rdoc b/doc/standard_library.rdoc
index fd5b8c567d..7e4c13b329 100644
--- a/doc/standard_library.rdoc
+++ b/doc/standard_library.rdoc
@@ -23,7 +23,6 @@ Gem:: Package management framework for Ruby
 SecureRandom:: Interface for secure random number generator
 Shellwords:: Manipulates strings with word parsing rules of UNIX Bourne shell
 Time:: Extends the Time class with methods for parsing and conversion
-TSort:: Topological sorting using Tarjan's algorithm
 un.rb:: Utilities to replace common UNIX commands
 
 == Extensions
@@ -80,6 +79,7 @@ Tempfile:: A utility class for managing temporary files
 Timeout:: Auto-terminate potentially long-running operations in Ruby
 tmpdir.rb:: Extends the Dir class to manage the OS temporary file path
 Tracer:: Outputs a source level execution trace of a Ruby program
+TSort:: Topological sorting using Tarjan's algorithm
 URI:: A Ruby module providing support for Uniform Resource Identifiers
 WEBrick:: An HTTP server toolkit for Ruby
 YAML:: Ruby client library for the Psych YAML implementation
diff --git a/lib/tsort.gemspec b/lib/tsort.gemspec
new file mode 100644
index 0000000000..4656d0b845
--- /dev/null
+++ b/lib/tsort.gemspec
@@ -0,0 +1,22 @@
+Gem::Specification.new do |spec|
+  spec.name          = "tsort"
+  spec.version       = "0.1.0"
+  spec.authors       = ["Tanaka Akira"]
+  spec.email         = ["akr@fsij.org"]
+
+  spec.summary       = %q{Topological sorting using Tarjan's algorithm}
+  spec.description   = %q{Topological sorting using Tarjan's algorithm}
+  spec.homepage      = "https://github.com/ruby/tsort"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+  spec.licenses      = ["Ruby", "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/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 1943eebfd1..8a672dbf34 100644
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -67,6 +67,7 @@ REPOSITORIES = {
   rinda: "ruby/rinda",
   erb: "ruby/erb",
   nkf: "ruby/nkf",
+  tsort: "ruby/tsort",
 }
 
 def sync_default_gems(gem)