diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
index c523723fc4..1bd97eed38 100644
--- a/activejob/CHANGELOG.md
+++ b/activejob/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Include I18n.locale into job serialization/deserialization and use it around
+    `perform`.
+
+    Fixes #20799.
+
+    *Johannes Opper*
+
 *   Allow `DelayedJob`, `Sidekiq`, `qu`, and `que` to report the job id back to
     `ActiveJob::Base` as `provider_job_id`.
 
diff --git a/activejob/lib/active_job/base.rb b/activejob/lib/active_job/base.rb
index fd49b3fda5..5d7c4cfb91 100644
--- a/activejob/lib/active_job/base.rb
+++ b/activejob/lib/active_job/base.rb
@@ -5,6 +5,7 @@ require 'active_job/enqueuing'
 require 'active_job/execution'
 require 'active_job/callbacks'
 require 'active_job/logging'
+require 'active_job/translation'
 
 module ActiveJob #:nodoc:
   # = Active Job
@@ -60,6 +61,7 @@ module ActiveJob #:nodoc:
     include Execution
     include Callbacks
     include Logging
+    include Translation
 
     ActiveSupport.run_load_hooks(:active_job, self)
   end
diff --git a/activejob/lib/active_job/core.rb b/activejob/lib/active_job/core.rb
index 0528572cd0..eac7279309 100644
--- a/activejob/lib/active_job/core.rb
+++ b/activejob/lib/active_job/core.rb
@@ -20,6 +20,9 @@ module ActiveJob
 
       # ID optionally provided by adapter
       attr_accessor :provider_job_id
+
+      # I18n.locale to be used during the job.
+      attr_accessor :locale
     end
 
     # These methods will be included into any Active Job object, adding
@@ -68,7 +71,8 @@ module ActiveJob
         'job_class'  => self.class.name,
         'job_id'     => job_id,
         'queue_name' => queue_name,
-        'arguments'  => serialize_arguments(arguments)
+        'arguments'  => serialize_arguments(arguments),
+        'locale'     => I18n.locale
       }
     end
 
@@ -96,6 +100,7 @@ module ActiveJob
       self.job_id               = job_data['job_id']
       self.queue_name           = job_data['queue_name']
       self.serialized_arguments = job_data['arguments']
+      self.locale               = job_data['locale'] || I18n.locale
     end
 
     private
diff --git a/activejob/lib/active_job/translation.rb b/activejob/lib/active_job/translation.rb
new file mode 100644
index 0000000000..67e4cf4ab9
--- /dev/null
+++ b/activejob/lib/active_job/translation.rb
@@ -0,0 +1,11 @@
+module ActiveJob
+  module Translation #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      around_perform do |job, block, _|
+        I18n.with_locale(job.locale, &block)
+      end
+    end
+  end
+end
diff --git a/activejob/test/cases/job_serialization_test.rb b/activejob/test/cases/job_serialization_test.rb
index db22783030..e23380a7bf 100644
--- a/activejob/test/cases/job_serialization_test.rb
+++ b/activejob/test/cases/job_serialization_test.rb
@@ -12,4 +12,20 @@ class JobSerializationTest < ActiveSupport::TestCase
     GidJob.perform_later @person
     assert_equal "Person with ID: 5", JobBuffer.last_value
   end
+
+  test 'serialize includes current locale' do
+    assert_equal :en, HelloJob.new.serialize['locale']
+  end
+
+  test 'deserialize sets locale' do
+    job = HelloJob.new
+    job.deserialize 'locale' => :es
+    assert_equal :es, job.locale
+  end
+
+  test 'deserialize sets default locale' do
+    job = HelloJob.new
+    job.deserialize({})
+    assert_equal :en, job.locale
+  end
 end
diff --git a/activejob/test/cases/translation_test.rb b/activejob/test/cases/translation_test.rb
new file mode 100644
index 0000000000..d5e3aaf9e3
--- /dev/null
+++ b/activejob/test/cases/translation_test.rb
@@ -0,0 +1,20 @@
+require 'helper'
+require 'jobs/translated_hello_job'
+
+class TranslationTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+    I18n.available_locales = [:en, :de]
+    @job = TranslatedHelloJob.new('Johannes')
+  end
+
+  teardown do
+    I18n.available_locales = [:en]
+  end
+
+  test 'it performs the job in the given locale' do
+    @job.locale = :de
+    @job.perform_now
+    assert_equal "Johannes says Guten Tag", JobBuffer.last_value
+  end
+end
diff --git a/activejob/test/integration/queuing_test.rb b/activejob/test/integration/queuing_test.rb
index d345092dee..e1634972d1 100644
--- a/activejob/test/integration/queuing_test.rb
+++ b/activejob/test/integration/queuing_test.rb
@@ -68,4 +68,21 @@ class QueuingTest < ActiveSupport::TestCase
     refute delayed_test_job.provider_job_id.nil?,
       'Provider job id should by set for delayed jobs by provider'
   end
+
+  test 'current locale is kept while running perform_later' do
+    skip if adapter_is?(:inline)
+
+    begin
+      I18n.available_locales = [:en, :de]
+      I18n.locale = :de
+
+      TestJob.perform_later @id
+      wait_for_jobs_to_finish_for(5.seconds)
+      assert job_executed
+      assert_equal 'de', job_output
+    ensure
+      I18n.available_locales = [:en]
+      I18n.locale = :en
+    end
+  end
 end
diff --git a/activejob/test/jobs/translated_hello_job.rb b/activejob/test/jobs/translated_hello_job.rb
new file mode 100644
index 0000000000..9657cd3f54
--- /dev/null
+++ b/activejob/test/jobs/translated_hello_job.rb
@@ -0,0 +1,10 @@
+require_relative '../support/job_buffer'
+
+class TranslatedHelloJob < ActiveJob::Base
+  def perform(greeter = "David")
+    translations = { en: 'Hello', de: 'Guten Tag' }
+    hello        = translations[I18n.locale]
+
+    JobBuffer.add("#{greeter} says #{hello}")
+  end
+end
diff --git a/activejob/test/support/integration/dummy_app_template.rb b/activejob/test/support/integration/dummy_app_template.rb
index 09a68738ad..4ffdb8cffa 100644
--- a/activejob/test/support/integration/dummy_app_template.rb
+++ b/activejob/test/support/integration/dummy_app_template.rb
@@ -8,13 +8,17 @@ require "#{File.expand_path("../jobs_manager.rb",  __FILE__)}"
 JobsManager.current_manager.setup
 CODE
 
+initializer 'i18n.rb', <<-CODE
+I18n.available_locales = [:en, :de]
+CODE
+
 file 'app/jobs/test_job.rb', <<-CODE
 class TestJob < ActiveJob::Base
   queue_as :integration_tests
 
   def perform(x)
     File.open(Rails.root.join("tmp/\#{x}"), "w+") do |f|
-      f.write x
+      f.write I18n.locale
     end
   end
 end
diff --git a/activejob/test/support/integration/test_case_helpers.rb b/activejob/test/support/integration/test_case_helpers.rb
index 7e87ede275..39aee6d407 100644
--- a/activejob/test/support/integration/test_case_helpers.rb
+++ b/activejob/test/support/integration/test_case_helpers.rb
@@ -45,4 +45,8 @@ module TestCaseHelpers
     def job_executed
       Dummy::Application.root.join("tmp/#{@id}").exist?
     end
+
+    def job_output
+      File.read Dummy::Application.root.join("tmp/#{@id}")
+    end
 end
diff --git a/guides/source/active_job_basics.md b/guides/source/active_job_basics.md
index 22f3c0146a..1715fc327a 100644
--- a/guides/source/active_job_basics.md
+++ b/guides/source/active_job_basics.md
@@ -280,6 +280,19 @@ UserMailer.welcome(@user).deliver_later
 ```
 
 
+Internationalization
+--------------------
+
+Each job uses the `I18n.locale` set when the job was created. Useful if you send
+emails asynchronously:
+
+```ruby
+I18n.locale = :eo
+
+UserMailer.welcome(@user).deliver_later # Email will be localized to Esparanto.
+```
+
+
 GlobalID
 --------