diff --git a/execjs.gemspec b/execjs.gemspec
index 3db8b7f..c0fb894 100644
--- a/execjs.gemspec
+++ b/execjs.gemspec
@@ -25,7 +25,7 @@ Gem::Specification.new do |s|
     "README.md"
   ]
 
-  s.add_dependency "multi_json", ">=1.0.0"
+  s.add_dependency "multi_json", "~>1.0"
   s.add_development_dependency "mustang"
   s.add_development_dependency "therubyracer"
   s.add_development_dependency "therubyrhino"