diff --git a/mechanize.gemspec b/mechanize.gemspec
index b448284f..e3a34c43 100644
--- a/mechanize.gemspec
+++ b/mechanize.gemspec
@@ -58,4 +58,6 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency "ntlm-http",            [ ">= 0.1.1", "~> 0.1"   ]
   spec.add_runtime_dependency "webrobots",            [ "< 0.2",    ">= 0.0.9" ]
   spec.add_runtime_dependency "domain_name",          [ ">= 0.5.1", "~> 0.5"   ]
+
+  spec.add_development_dependency 'webrick'
 end