diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index d1e5336..048b1ad 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -1323,6 +1323,10 @@
   call append("$", "pythonthreedll\tname of the Python 3 dynamic library")
   call <SID>OptionG("pythonthreedll", &pythonthreedll)
 endif
+if exists("&rubydll")
+  call append("$", "rubydll\tname of the Ruby dynamic library")
+  call <SID>OptionG("rubydll", &rubydll)
+endif
 
 set cpo&vim