diff --git a/actionpack/actionpack.gemspec b/actionpack/actionpack.gemspec
index ae26d6f9e5829..938f3d6dc2000 100644
--- a/actionpack/actionpack.gemspec
+++ b/actionpack/actionpack.gemspec
@@ -26,5 +26,5 @@ Gem::Specification.new do |s|
   s.add_dependency('journey',       '~> 1.0.1')
   s.add_dependency('erubis',        '~> 2.7.0')
 
-  s.add_development_dependency('tzinfo', '~> 0.3.29')
+  s.add_development_dependency('tzinfo', '~> 0.3.33')
 end
diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
index 30221f240175f..fa38d5c1e3268 100644
--- a/activesupport/activesupport.gemspec
+++ b/activesupport/activesupport.gemspec
@@ -21,5 +21,5 @@ Gem::Specification.new do |s|
 
   s.add_dependency('i18n',       '~> 0.6')
   s.add_dependency('multi_json', '~> 1.3')
-  s.add_dependency('tzinfo',     '~> 0.3.31')
+  s.add_dependency('tzinfo',     '~> 0.3.33')
 end