diff --git a/lib/net/protocol/net-protocol.gemspec b/lib/net/protocol/net-protocol.gemspec
new file mode 100644
index 0000000000..3ed57922fe
--- /dev/null
+++ b/lib/net/protocol/net-protocol.gemspec
@@ -0,0 +1,29 @@
+begin
+  require_relative "lib/net/protocol/version"
+rescue LoadError # Fallback to load version file in ruby core repository
+  require_relative "version"
+end
+
+Gem::Specification.new do |spec|
+  spec.name          = "net-protocol"
+  spec.version       = Net::Protocol::VERSION
+  spec.authors = ["Yukihiro Matsumoto"]
+  spec.email = ["matz@ruby-lang.org"]
+
+  spec.summary       = %q{The abstruct interface for net-* client.}
+  spec.description   = %q{The abstruct interface for net-* client.}
+  spec.homepage      = "https://github.com/ruby/net-protocol"
+  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  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/net/protocol/version.rb b/lib/net/protocol/version.rb
new file mode 100644
index 0000000000..f80c5187a2
--- /dev/null
+++ b/lib/net/protocol/version.rb
@@ -0,0 +1,5 @@
+module Net
+  class Protocol
+    VERSION = "0.1.0"
+  end
+end
\ No newline at end of file
diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 31604e06ed..2ca3c24ec1 100644
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -59,6 +59,7 @@
 # * https://github.com/ruby/tempfile
 # * https://github.com/ruby/tmpdir
 # * https://github.com/ruby/English
+# * https://github.com/ruby/net-protocol
 #
 
 require 'fileutils'
@@ -116,6 +117,7 @@ $repositories = {
   tempfile: "ruby/tempfile",
   tmpdir: "ruby/tmpdir",
   English: "ruby/English",
+  "net-protocol": "ruby/net-protocol",
 }
 
 def sync_default_gems(gem)
@@ -274,6 +276,9 @@ def sync_default_gems(gem)
   when "net-smtp"
     sync_lib "net-smtp"
     mv "lib/net-smtp.gemspec", "lib/net/smtp"
+  when "net-protocol"
+    sync_lib "net-protocol"
+    mv "lib/net-protocol.gemspec", "lib/net/protocol"
   when "readline-ext"
     rm_rf(%w[ext/readline test/readline])
     cp_r("#{upstream}/ext/readline", "ext")