diff --git a/lib/rails/auth/helpers.rb b/lib/rails/auth/helpers.rb
index 359361e..12197d9 100644
--- a/lib/rails/auth/helpers.rb
+++ b/lib/rails/auth/helpers.rb
@@ -24,7 +24,7 @@ def authorized?(rack_env)
 
     # Mark what authorized the request in the Rack environment
     #
-    # @param [Hash] :env Rack environment
+    # @param [Hash] :rack_env Rack environment
     # @param [String] :allowed_by what allowed this request
     def set_allowed_by(rack_env, allowed_by)
       Env.new(rack_env).tap do |env|