diff --git a/devise.gemspec b/devise.gemspec
index 491832eb..c4cf7fac 100644
--- a/devise.gemspec
+++ b/devise.gemspec
@@ -22,6 +22,6 @@ Gem::Specification.new do |s|
   s.add_dependency("orm_adapter", "~> 0.1")
   s.add_dependency("bcrypt", "~> 3.0")
   s.add_dependency("thread_safe", "~> 0.1")
-  s.add_dependency("railties", ">= 4.1.0", "< 5")
+  s.add_dependency("railties", ">= 4.1.0", "< 5.1")
   s.add_dependency("responders")
 end