diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index 88ee07d95bb2a576e34643c8111d4cf063979e1f..9d1e0d3ac56a59cb0bd682351bc0b186c22cfb3d 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -204,7 +204,7 @@ def load!
 
     private
       def valid_extension?(extension)
-        Template.template_handler_extensions.include?(extension)
+        !Template.registered_template_handler(extension).nil?
       end
 
       def find_full_path(path, load_paths)
diff --git a/actionpack/lib/action_view/template_handlers.rb b/actionpack/lib/action_view/template_handlers.rb
index d06ddd5fb55632d692d714eaa4425b8f3817680c..205f8628f0e97e791e24639822342c6470dc2917 100644
--- a/actionpack/lib/action_view/template_handlers.rb
+++ b/actionpack/lib/action_view/template_handlers.rb
@@ -32,13 +32,17 @@ def template_handler_extensions
       @@template_handlers.keys.map(&:to_s).sort
     end
 
+    def registered_template_handler(extension)
+      extension && @@template_handlers[extension.to_sym]
+    end
+
     def register_default_template_handler(extension, klass)
       register_template_handler(extension, klass)
       @@default_template_handlers = klass
     end
 
     def handler_class_for_extension(extension)
-      (extension && @@template_handlers[extension.to_sym]) || @@default_template_handlers
+      registered_template_handler(extension) || @@default_template_handlers
     end
   end
 end