diff --git a/actionmailer/test/message_delivery_test.rb b/actionmailer/test/message_delivery_test.rb
index 862ce26187fe476f12c137ee04aa1d4323f52a9d..b834cdd08ccc3d0fd6a5d905d1f0474049e82394 100644
--- a/actionmailer/test/message_delivery_test.rb
+++ b/actionmailer/test/message_delivery_test.rb
@@ -1,6 +1,5 @@
 require 'abstract_unit'
 require 'active_job'
-require 'minitest/mock'
 require 'mailers/delayed_mailer'
 
 class MessageDeliveryTest < ActiveSupport::TestCase
diff --git a/actionpack/test/controller/parameters/always_permitted_parameters_test.rb b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
index 59be08db54265aaf267f266c3313777ecadfa43e..efaf8a96c3e5d291b6edf35060e7a1b3457d8b17 100644
--- a/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
+++ b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
@@ -1,6 +1,5 @@
 require 'abstract_unit'
 require 'action_controller/metal/strong_parameters'
-require 'minitest/mock'
 
 class AlwaysPermittedParametersTest < ActiveSupport::TestCase
   def setup
diff --git a/activemodel/test/cases/helper.rb b/activemodel/test/cases/helper.rb
index c100646837b423b9abe14d4ac5a4b9d4d68c55fa..0cd80be66fc3ec83e11da94c386699def006f3bb 100644
--- a/activemodel/test/cases/helper.rb
+++ b/activemodel/test/cases/helper.rb
@@ -13,8 +13,6 @@
 require 'active_support/testing/autorun'
 require 'active_support/testing/method_call_assertions'
 
-require 'minitest/mock'
-
 # Skips the current run on Rubinius using Minitest::Assertions#skip
 def rubinius_skip(message = '')
   skip message if RUBY_ENGINE == 'rbx'
diff --git a/activesupport/test/abstract_unit.rb b/activesupport/test/abstract_unit.rb
index 65a8edbabb527db51b301c5c04d895ad7e1556a5..c0e23e89f77fb4f8bc1da8a61b9d22c9450aaf70 100644
--- a/activesupport/test/abstract_unit.rb
+++ b/activesupport/test/abstract_unit.rb
@@ -38,8 +38,6 @@ def jruby_skip(message = '')
   skip message if defined?(JRUBY_VERSION)
 end
 
-require 'minitest/mock'
-
 class ActiveSupport::TestCase
   include ActiveSupport::Testing::MethodCallAssertions
 end
diff --git a/railties/test/generators/named_base_test.rb b/railties/test/generators/named_base_test.rb
index 1c32fc1bfd5f3ed6672921e959288705a5ec6268..291f5e06c365b4e6a664cbfa3bded70e69cc69ae 100644
--- a/railties/test/generators/named_base_test.rb
+++ b/railties/test/generators/named_base_test.rb
@@ -1,6 +1,5 @@
 require 'generators/generators_test_helper'
 require 'rails/generators/rails/scaffold_controller/scaffold_controller_generator'
-require 'minitest/mock'
 
 class NamedBaseTest < Rails::Generators::TestCase
   include GeneratorsTestHelper