diff --git a/lib/jekyll/tags/highlight.rb b/lib/jekyll/tags/highlight.rb
index 687ef8c8..2ea144df 100644
--- a/lib/jekyll/tags/highlight.rb
+++ b/lib/jekyll/tags/highlight.rb
@@ -13,8 +13,8 @@ module Jekyll
 
       def initialize(tag_name, markup, tokens)
         super
-        if markup.downcase.strip =~ SYNTAX
-          @lang = $1
+        if markup.strip =~ SYNTAX
+          @lang = $1.downcase
           @options = {}
           if defined?($2) && $2 != ''
             $2.split.each do |opt|