diff --git a/webmock.gemspec b/webmock.gemspec
index d7ff8578d..a493d5a11 100644
--- a/webmock.gemspec
+++ b/webmock.gemspec
@@ -45,6 +45,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'minitest',        '>= 5.0.0'
   s.add_development_dependency 'test-unit',       '>= 3.0.0'
   s.add_development_dependency 'rdoc',            '>  3.5.0'
+  s.add_development_dependency 'webrick'
 
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")