diff --git a/public_ip.gemspec b/public_ip.gemspec
index 5e7af19..b8df7f6 100644
--- a/public_ip.gemspec
+++ b/public_ip.gemspec
@@ -23,6 +23,8 @@ DESCRIPTION
   spec.executables   = ['public_ip']
   spec.require_paths = ['lib']
 
+  spec.required_ruby_version = '>= 2.0'
+
   spec.add_dependency 'methadone', '~> 1.9.2'
   spec.add_dependency 'nokogiri', '~> 1.6.7'