diff --git a/Library/Homebrew/cmd/tap-readme.rb b/Library/Homebrew/cmd/tap-readme.rb
index be058ebf5d..2845cc85bc 100644
--- a/Library/Homebrew/cmd/tap-readme.rb
+++ b/Library/Homebrew/cmd/tap-readme.rb
@@ -4,7 +4,7 @@ module Homebrew
     raise "A name is required" if name.nil?
 
     titleized_name = name.dup
-    titleized_name[0] = titleized_name[0].upcase
+    titleized_name[0..0] = titleized_name[0..0].upcase
 
     template = <<-EOS.undent
     # Homebrew #{titleized_name}