diff --git a/lib/active_model/serializable.rb b/lib/active_model/serializable.rb
index 944cb0aa..897ea13f 100644
--- a/lib/active_model/serializable.rb
+++ b/lib/active_model/serializable.rb
@@ -3,11 +3,19 @@ module ActiveModel
     def as_json(options={})
       if root = options[:root] || self.root
         hash = { root.to_s => serializable_object }
-        hash[meta_key.to_s] = meta if meta
+        hash.merge!(serializable_data)
         hash
       else
         serializable_object
       end
     end
+
+    def serializable_data
+      if respond_to?(:meta) && meta
+        { meta_key.to_s => meta }
+      else
+        {}
+      end
+    end
   end
 end
diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index 7fa1a31f..a7af3235 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -70,15 +70,20 @@ module ActiveModel
     def initialize(object, options={})
       @object   = object
       @scope    = options[:scope]
-      @root     = options[:root] || self.class._root
-      @root     = self.class.root_name if @root == true
+      self.root = options[:root]
       @meta_key = options[:meta_key] || :meta
       @meta     = options[@meta_key]
     end
-    attr_accessor :object, :scope, :root, :meta_key, :meta
+    attr_accessor :object, :scope, :meta_key, :meta
+    attr_reader :root
 
     alias read_attribute_for_serialization send
 
+    def root=(root)
+      @root = root || self.class._root
+      @root = self.class.root_name if auto_assign_root?
+    end
+
     def attributes
       self.class._attributes.each_with_object({}) do |name, hash|
         hash[name] = send(name)
@@ -89,8 +94,19 @@ module ActiveModel
       self.class._associations.each_with_object({}) do |association, hash|
         if association.embed_ids?
           hash[association.key] = serialize_ids association
+        elsif association.embed_objects?
+          hash[association.embedded_key] = serialize association
         end
-        if association.embed_objects?
+      end
+    end
+
+    def serializable_data
+      embedded_in_root_associations.merge!(super)
+    end
+
+    def embedded_in_root_associations
+      self.class._associations.each_with_object({}) do |association, hash|
+        if association.embed_in_root?
           hash[association.embedded_key] = serialize association
         end
       end
@@ -120,5 +136,11 @@ module ActiveModel
       hash.merge! associations
     end
     alias serializable_object serializable_hash
+
+    private
+
+    def auto_assign_root?
+      @root == true || !@root && self.class._associations.any? { |a| a.embed_in_root? }
+    end
   end
 end
diff --git a/lib/active_model/serializer/associations.rb b/lib/active_model/serializer/associations.rb
index 369b2eff..91d473fc 100644
--- a/lib/active_model/serializer/associations.rb
+++ b/lib/active_model/serializer/associations.rb
@@ -7,20 +7,20 @@ module ActiveModel
         @name          = name
         @options       = options
 
-        self.embed    = options[:embed]
-        @embed_key    = options[:embed_key] || :id
-        @include      = options[:include]
-        @key          = options[:key]
-        @embedded_key = options[:root]
+        self.embed     = options[:embed]
+        @embed_in_root = @embed_ids && options[:include]
+        @embed_key     = options[:embed_key] || :id
+        @key           = options[:key]
+        @embedded_key  = options[:root]
 
         self.serializer_class = @options[:serializer]
       end
 
-      attr_reader :name, :embed_ids, :embed_objects, :embed_key, :serializer_class, :options
-      attr_accessor :include, :key, :embedded_key
+      attr_reader :name, :embed_ids, :embed_objects, :serializer_class
+      attr_accessor :embed_in_root, :embed_key, :key, :embedded_key, :options
       alias embed_ids? embed_ids
       alias embed_objects? embed_objects
-      alias include? include
+      alias embed_in_root? embed_in_root
 
       def serializer_class=(serializer)
         @serializer_class = serializer.is_a?(String) ? serializer.constantize : serializer
@@ -31,10 +31,6 @@ module ActiveModel
         @embed_objects = embed == :object || embed == :objects
       end
 
-      def embed_objects?
-        @embed_objects || @embed_ids && @include
-      end
-
       def build_serializer(object)
         @serializer_class ||= Serializer.serializer_for(object)
 
diff --git a/test/unit/active_model/serializer/has_many_test.rb b/test/unit/active_model/serializer/has_many_test.rb
index efab83e5..a4837a5b 100644
--- a/test/unit/active_model/serializer/has_many_test.rb
+++ b/test/unit/active_model/serializer/has_many_test.rb
@@ -4,11 +4,15 @@ module ActiveModel
   class Serializer
     class HasManyTest < ActiveModel::TestCase
       def setup
+        @association = PostSerializer._associations[0]
+        @old_association = @association.dup
+        @association.embed = :ids
         @post = Post.new({ title: 'Title 1', body: 'Body 1', date: '1/1/2000' })
         @post_serializer = PostSerializer.new(@post)
-        @association = PostSerializer._associations[0]
-        @association.include = false
-        @association.embed = :ids
+      end
+
+      def teardown
+        PostSerializer._associations[0] = @old_association
       end
 
       def test_associations_definition
@@ -30,13 +34,10 @@ module ActiveModel
       end
 
       def test_associations_embedding_ids_serialization_using_serializable_hash_and_key_from_options
-        old_key = @association.key
         @association.key = 'key'
         assert_equal({
           'title' => 'Title 1', 'body' => 'Body 1', 'key' => @post.comments.map { |c| c.object_id }
         }, @post_serializer.serializable_hash)
-      ensure
-        @association.key = old_key
       end
 
       def test_associations_embedding_objects_serialization_using_serializable_hash
@@ -55,32 +56,32 @@ module ActiveModel
 
       def test_associations_embedding_objects_serialization_using_serializable_hash_and_root_from_options
         @association.embed = :objects
-        old_embedded_key = @association.embedded_key
         @association.embedded_key = 'root'
         assert_equal({
           'title' => 'Title 1', 'body' => 'Body 1', 'root' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
         }, @post_serializer.serializable_hash)
-      ensure
-        @association.embedded_key = old_embedded_key
       end
 
       def test_associations_embedding_ids_including_objects_serialization_using_serializable_hash
-       @association.include = true
+        @association.embed_in_root = true
+        @post_serializer.root = nil
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }, 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }
         }, @post_serializer.serializable_hash)
       end
 
       def test_associations_embedding_ids_including_objects_serialization_using_as_json
-        @association.include = true
+        @association.embed_in_root = true
+        @post_serializer.root = nil
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }, 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+          'post' => { 'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id } },
+          'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
         }, @post_serializer.as_json)
       end
 
       def test_associations_using_a_given_serializer
-        @old_serializer = @association.serializer_class
-        @association.include = true
+        @association.embed_in_root = true
+        @post_serializer.root = nil
         @association.serializer_class = Class.new(ActiveModel::Serializer) do
           def content
             'fake'
@@ -90,10 +91,9 @@ module ActiveModel
         end
 
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }, 'comments' => [{ 'content' => 'fake' }, { 'content' => 'fake' }]
+          'post' => { 'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id } },
+          'comments' => [{ 'content' => 'fake' }, { 'content' => 'fake' }]
         }, @post_serializer.as_json)
-      ensure
-        @association.serializer_class = @old_serializer
       end
     end
   end
diff --git a/test/unit/active_model/serializer/has_one_test.rb b/test/unit/active_model/serializer/has_one_test.rb
index 2a34426b..f7028548 100644
--- a/test/unit/active_model/serializer/has_one_test.rb
+++ b/test/unit/active_model/serializer/has_one_test.rb
@@ -4,11 +4,15 @@ module ActiveModel
   class Serializer
     class HasOneTest < ActiveModel::TestCase
       def setup
+        @association = UserSerializer._associations[0]
+        @old_association = @association.dup
+        @association.embed = :ids
         @user = User.new({ name: 'Name 1', email: 'mail@server.com', gender: 'M' })
         @user_serializer = UserSerializer.new(@user)
-        @association = UserSerializer._associations[0]
-        @association.include = false
-        @association.embed = :ids
+      end
+
+      def teardown
+        UserSerializer._associations[0] = @old_association
       end
 
       def test_associations_definition
@@ -30,13 +34,10 @@ module ActiveModel
       end
 
       def test_associations_embedding_ids_serialization_using_serializable_hash_and_key_from_options
-        old_key = @association.key
         @association.key = 'key'
         assert_equal({
           'name' => 'Name 1', 'email' => 'mail@server.com', 'key' => @user.profile.object_id
         }, @user_serializer.serializable_hash)
-      ensure
-        @association.key = old_key
       end
 
       def test_associations_embedding_objects_serialization_using_serializable_hash
@@ -55,32 +56,32 @@ module ActiveModel
 
       def test_associations_embedding_objects_serialization_using_serializable_hash_and_root_from_options
         @association.embed = :objects
-        old_embedded_key = @association.embedded_key
         @association.embedded_key = 'root'
         assert_equal({
           'name' => 'Name 1', 'email' => 'mail@server.com', 'root' => [{ 'name' => 'N1', 'description' => 'D1' }]
         }, @user_serializer.serializable_hash)
-      ensure
-        @association.embedded_key = old_embedded_key
       end
 
       def test_associations_embedding_ids_including_objects_serialization_using_serializable_hash
-        @association.include = true
+        @association.embed_in_root = true
+        @user_serializer.root = nil
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id, 'profiles' => [{ 'name' => 'N1', 'description' => 'D1' }]
+          'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id
         }, @user_serializer.serializable_hash)
       end
 
       def test_associations_embedding_ids_including_objects_serialization_using_as_json
-        @association.include = true
+        @association.embed_in_root = true
+        @user_serializer.root = nil
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id, 'profiles' => [{ 'name' => 'N1', 'description' => 'D1' }]
+          'user' => { 'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id },
+          'profiles' => [{ 'name' => 'N1', 'description' => 'D1' }]
         }, @user_serializer.as_json)
       end
 
       def test_associations_using_a_given_serializer
-        @old_serializer = @association.serializer_class
-        @association.include = true
+        @association.embed_in_root = true
+        @user_serializer.root = nil
         @association.serializer_class = Class.new(ActiveModel::Serializer) do
           def name
             'fake'
@@ -90,10 +91,9 @@ module ActiveModel
         end
 
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id, 'profiles' => [{ 'name' => 'fake' }]
+          'user' => { 'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id },
+          'profiles' => [{ 'name' => 'fake' }]
         }, @user_serializer.as_json)
-      ensure
-        @association.serializer_class = @old_serializer
       end
     end
   end