diff --git a/lib/ace/mode/ruby_highlight_rules.js b/lib/ace/mode/ruby_highlight_rules.js
index 73e3302c..27187068 100644
--- a/lib/ace/mode/ruby_highlight_rules.js
+++ b/lib/ace/mode/ruby_highlight_rules.js
@@ -62,7 +62,7 @@ RubyHighlightRules = function() {
     );
 
     var builtinVariables = lang.arrayToMap(
-        ("\\$DEBUG|\\$defout|\\$FILENAME|\\$LOAD_PATH|\\$SAFE|\\$stdin|\\$stdout|\\$stderr|\\$VERBOSE").split("|")
+        ("\$DEBUG|\$defout|\$FILENAME|\$LOAD_PATH|\$SAFE|\$stdin|\$stdout|\$stderr|\$VERBOSE").split("|")
     );
 
     // regexp must not have capturing parentheses. Use (?:) instead.