diff --git a/active_model_serializers.gemspec b/active_model_serializers.gemspec
index 0971a26e..9711c564 100644
--- a/active_model_serializers.gemspec
+++ b/active_model_serializers.gemspec
@@ -17,7 +17,10 @@ Gem::Specification.new do |gem|
   gem.require_paths = ["lib"]
   gem.version       = ActiveModel::Serializer::VERSION
 
-  gem.add_dependency 'activemodel', '>= 3.0'
+  gem.required_ruby_version = ">= 1.9.2"
+
+  gem.add_dependency "activemodel", ">= 3.0"
+
   gem.add_development_dependency "rails", ">= 3.0"
   gem.add_development_dependency "pry"
   gem.add_development_dependency "simplecov"