diff --git a/hamlit.gemspec b/hamlit.gemspec
index 52dc9f7a..b5ec1ae2 100644
--- a/hamlit.gemspec
+++ b/hamlit.gemspec
@@ -19,6 +19,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.extensions    = ['ext/hamlit/extconf.rb']
   spec.require_paths = ['lib']
+  spec.required_ruby_version = '>= 2.1.0'
 
   spec.add_dependency 'temple', '~> 0.7.6'
   spec.add_dependency 'thor'