diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
index 3c2402c136..d26d71b615 100644
--- a/activesupport/activesupport.gemspec
+++ b/activesupport/activesupport.gemspec
@@ -20,5 +20,5 @@ Gem::Specification.new do |s|
 
   s.add_dependency('i18n',       '~> 0.6')
   s.add_dependency('multi_json', '~> 1.0')
-  s.add_dependency('tzinfo',     '~> 0.3.29')
+  s.add_dependency('tzinfo',     '~> 0.3.31')
 end