diff --git a/lib/irb/ruby-lex.rb b/lib/irb/ruby-lex.rb
index 3b62ef8676..2dd2b7b343 100644
--- a/lib/irb/ruby-lex.rb
+++ b/lib/irb/ruby-lex.rb
@@ -300,7 +300,8 @@ class RubyLex
     "Q" => "\"",
     "x" => "\`",
     "r" => "\/",
-    "w" => "]"
+    "w" => "]",
+    "W" => "]"
   }
   
   PERCENT_PAREN = {