diff --git a/mrbgems/mruby-io/mrbgem.rake b/mrbgems/mruby-io/mrbgem.rake
index 63933c7b1..b9118713b 100644
--- a/mrbgems/mruby-io/mrbgem.rake
+++ b/mrbgems/mruby-io/mrbgem.rake
@@ -5,4 +5,8 @@ MRuby::Gem::Specification.new('mruby-io') do |spec|
 
   spec.build.defines << "HAVE_MRUBY_IO_GEM"
   spec.add_test_dependency 'mruby-time', core: 'mruby-time'
+
+  if spec.for_windows?
+    spec.linker.libraries << "ws2_32"
+  end
 end