diff --git a/Gemfile b/Gemfile
index c6c04a8..9b9c0bf 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,6 +9,4 @@ gem 'overcommit', '0.53.0'
 # Pin tool versions (which are executed by Overcommit) for Travis builds
 gem 'rubocop', '0.82.0'
 
-gem 'ruby2_keywords'
-
 gem 'coveralls', require: false
diff --git a/mock_redis.gemspec b/mock_redis.gemspec
index 1002d43..6637447 100644
--- a/mock_redis.gemspec
+++ b/mock_redis.gemspec
@@ -26,5 +26,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'redis', '~> 4.2.0'
   s.add_development_dependency 'rspec', '~> 3.0'
   s.add_development_dependency 'rspec-its', '~> 1.0'
+  s.add_development_dependency 'ruby2_keywords'
   s.add_development_dependency 'timecop', '~> 0.9.1'
 end