diff --git a/suo.gemspec b/suo.gemspec
index 027b35b..2dc1f41 100644
--- a/suo.gemspec
+++ b/suo.gemspec
@@ -20,6 +20,8 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
+  spec.required_ruby_version = "~> 2.0"
+
   spec.add_dependency "dalli"
   spec.add_dependency "redis"
   spec.add_dependency "msgpack"