diff --git a/twitter_cldr.gemspec b/twitter_cldr.gemspec
index a37bc57a9..6d1eadcf8 100644
--- a/twitter_cldr.gemspec
+++ b/twitter_cldr.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |s|
   s.has_rdoc = true
   s.summary  = "Ruby implementation of the ICU (International Components for Unicode) that uses the Common Locale Data Repository to format dates, plurals, and more."
 
-  s.add_dependency 'json'
+  s.add_dependency 'json', '~> 1.0'
   s.add_dependency 'camertron-eprun'
   s.add_dependency 'tzinfo'
   s.add_dependency 'cldr-plurals-runtime-rb', '~> 1.0.0'