diff --git a/Gemfile b/Gemfile
index e388355..931e6b9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,6 +7,12 @@ gemspec
 gem "rake"
 gem "minitest"
 
+# MT6 restricts supported versions, therefore older Rubies sticks with MT5,
+# which includes `minitest/mock`
+if RUBY_VERSION >= "3.2"
+  gem "minitest-mock"
+end
+
 group :rubocop do
   gem "rubocop", ">= 1.25.1", require: false
   gem "rubocop-minitest", require: false
diff --git a/test/rails_api_test.rb b/test/rails_api_test.rb
index 9bc1107..df4849d 100644
--- a/test/rails_api_test.rb
+++ b/test/rails_api_test.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "minitest/autorun"
+require "minitest/mock"
 require "rails-html-sanitizer"
 
 class RailsApiTest < Minitest::Test