diff --git a/Gemfile b/Gemfile
index 189e90a99..569775da3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,5 +14,5 @@ gem 'coderay', '1.1.3'
 gem 'pygments.rb', '2.4.1'
 gem 'thread_safe', '0.3.6'
 gem 'epubcheck-ruby', '5.1.0.0'
-gem 'html-proofer', '5.0.8'
+gem 'html-proofer', '5.0.9'
 gem 'kindlegen', '3.1.1'