diff --git a/active_paypal_adaptive_payment.gemspec b/active_paypal_adaptive_payment.gemspec
index 11e8673..92729f1 100644
--- a/active_paypal_adaptive_payment.gemspec
+++ b/active_paypal_adaptive_payment.gemspec
@@ -19,5 +19,5 @@ Gem::Specification.new do |s|
   s.add_dependency(%q<multi_json>, [">= 1.0.0"])
   s.add_dependency(%q<hashie>, [">= 1.2.0"])
   s.add_dependency(%q<money>, [">= 3.6.0"])
-  s.add_dependency(%q<mocha>, [">= 0.10.0"])
+  s.add_development_dependency(%q<mocha>, [">= 0.10.0"])
 end