diff --git a/Gemfile b/Gemfile
index 388a1efcc..baf12948d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -15,7 +15,3 @@ if version == "master"
 else
   gem "rails", "~> #{version}.0"
 end
-
-group :test do
-  gem "timecop"
-end
\ No newline at end of file
diff --git a/active_model_serializers.gemspec b/active_model_serializers.gemspec
index 3ae91fc15..a0279e3d6 100644
--- a/active_model_serializers.gemspec
+++ b/active_model_serializers.gemspec
@@ -22,5 +22,6 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency "rails", ">= 4.0"
   spec.add_development_dependency "bundler", "~> 1.6"
+  spec.add_development_dependency "timecop", ">= 0.7"
   spec.add_development_dependency "rake"
 end