diff --git a/activesupport/lib/active_support/core_ext/object/json.rb b/activesupport/lib/active_support/core_ext/object/json.rb
index 8ba694266d..75fae96dc6 100644
--- a/activesupport/lib/active_support/core_ext/object/json.rb
+++ b/activesupport/lib/active_support/core_ext/object/json.rb
@@ -49,6 +49,12 @@ end
   klass.prepend(ActiveSupport::ToJsonWithActiveSupportEncoder)
 end
 
+class Module
+  def as_json(options = nil) #:nodoc:
+    name
+  end
+end
+
 class Object
   def as_json(options = nil) #:nodoc:
     if respond_to?(:to_hash)
diff --git a/activesupport/test/json/encoding_test_cases.rb b/activesupport/test/json/encoding_test_cases.rb
index daf662051a..662e30c68c 100644
--- a/activesupport/test/json/encoding_test_cases.rb
+++ b/activesupport/test/json/encoding_test_cases.rb
@@ -68,6 +68,10 @@ module JSONTest
                      [ :this,  %("this") ],
                      [ :"a b", %("a b")  ]]
 
+    ModuleTests   = [[ Module, %("Module") ],
+                     [ Class,  %("Class")  ],
+                     [ ActiveSupport,                   %("ActiveSupport")                   ],
+                     [ ActiveSupport::MessageEncryptor, %("ActiveSupport::MessageEncryptor") ]]
     ObjectTests   = [[ Foo.new(1, 2), %({\"a\":1,\"b\":2}) ]]
     HashlikeTests = [[ Hashlike.new, %({\"bar\":\"world\",\"foo\":\"hello\"}) ]]
     StructTests   = [[ MyStruct.new(:foo, "bar"), %({\"name\":\"foo\",\"value\":\"bar\"}) ],