diff --git a/json-java.gemspec b/json-java.gemspec
index 87d8c87f..b766fa2f 100644
--- a/json-java.gemspec
+++ b/json-java.gemspec
@@ -1,5 +1,3 @@
-# -*- encoding: utf-8 -*-
-
 spec = Gem::Specification.new do |s|
   s.name = "json"
   s.version = File.read("VERSION").chomp
diff --git a/json.gemspec b/json.gemspec
index f4b2ae79..9cd4ceee 100644
--- a/json.gemspec
+++ b/json.gemspec
@@ -1,5 +1,3 @@
-# -*- encoding: utf-8 -*-
-
 Gem::Specification.new do |s|
   s.name = "json"
   s.version = File.read(File.expand_path('../VERSION', __FILE__)).chomp
diff --git a/json_pure.gemspec b/json_pure.gemspec
index 883beb0e..7b42a714 100644
--- a/json_pure.gemspec
+++ b/json_pure.gemspec
@@ -1,5 +1,3 @@
-# -*- encoding: utf-8 -*-
-
 Gem::Specification.new do |s|
   s.name = "json_pure".freeze
   s.version = File.read("VERSION").chomp
diff --git a/tests/json_encoding_test.rb b/tests/json_encoding_test.rb
index 68a058f7..be87f3c3 100644
--- a/tests/json_encoding_test.rb
+++ b/tests/json_encoding_test.rb
@@ -1,5 +1,4 @@
-# encoding: utf-8
-#frozen_string_literal: false
+# frozen_string_literal: false
 require_relative 'test_helper'
 
 class JSONEncodingTest < Test::Unit::TestCase
diff --git a/tests/json_generator_test.rb b/tests/json_generator_test.rb
index 09e56e53..526bb8c1 100755
--- a/tests/json_generator_test.rb
+++ b/tests/json_generator_test.rb
@@ -1,5 +1,4 @@
 #!/usr/bin/env ruby
-# encoding: utf-8
 # frozen_string_literal: false
 
 require_relative 'test_helper'
diff --git a/tests/ractor_test.rb b/tests/ractor_test.rb
index 2b4115b0..ba9bf7a7 100644
--- a/tests/ractor_test.rb
+++ b/tests/ractor_test.rb
@@ -1,4 +1,3 @@
-# encoding: utf-8
 # frozen_string_literal: false
 
 require_relative 'test_helper'
diff --git a/tools/server.rb b/tools/server.rb
index 184a01c6..084377fa 100755
--- a/tools/server.rb
+++ b/tools/server.rb
@@ -1,5 +1,4 @@
 #!/usr/bin/env ruby
-# encoding: utf-8
 
 require 'webrick'
 include WEBrick