diff --git a/lib/i18n/backend/chain.rb b/lib/i18n/backend/chain.rb
index 525dd2de..2d9d8ff3 100644
--- a/lib/i18n/backend/chain.rb
+++ b/lib/i18n/backend/chain.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'i18n/core_ext/hash'
+
 module I18n
   module Backend
     # Backend that chains multiple other backends and checks each of them when
diff --git a/lib/i18n/backend/gettext.rb b/lib/i18n/backend/gettext.rb
index 07696463..50d85805 100644
--- a/lib/i18n/backend/gettext.rb
+++ b/lib/i18n/backend/gettext.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'i18n/core_ext/hash'
 require 'i18n/gettext'
 require 'i18n/gettext/po_parser'
 
diff --git a/test/backend/chain_test.rb b/test/backend/chain_test.rb
index b5633746..953f62c7 100644
--- a/test/backend/chain_test.rb
+++ b/test/backend/chain_test.rb
@@ -1,4 +1,5 @@
 require 'test_helper'
+require 'i18n/backend/chain'
 
 class I18nBackendChainTest < I18n::TestCase
   def setup
diff --git a/test/gettext/backend_test.rb b/test/gettext/backend_test.rb
index 30254e6b..15c93123 100644
--- a/test/gettext/backend_test.rb
+++ b/test/gettext/backend_test.rb
@@ -1,6 +1,7 @@
 # encoding: utf-8
 
 require 'test_helper'
+require 'i18n/backend/gettext'
 
 class I18nGettextBackendTest < I18n::TestCase
   include I18n::Gettext::Helpers