diff --git a/lib/app_store_connect/object/data.rb b/lib/app_store_connect/object/data.rb
index fefc5dc..6530c16 100644
--- a/lib/app_store_connect/object/data.rb
+++ b/lib/app_store_connect/object/data.rb
@@ -33,12 +33,6 @@ def to_h
         end
 
         const_set('Data', klass)
-
-        def to_h
-          {
-            data: data.to_h
-          }
-        end
       end
 
       class_methods do
diff --git a/lib/app_store_connect/object/included.rb b/lib/app_store_connect/object/included.rb
new file mode 100644
index 0000000..1bc0720
--- /dev/null
+++ b/lib/app_store_connect/object/included.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'active_support/concern'
+
+module AppStoreConnect
+  module Object
+    module Included
+      extend ActiveSupport::Concern
+
+      included do
+        attr_reader :included
+
+        klass = Class.new do |i|
+          i.send(:define_method, :initialize) do |objects|
+            instance_variable_set('@objects', [*objects])
+          end
+
+          def to_a
+            @objects
+          end
+        end
+
+        const_set('Included', klass)
+      end
+    end
+  end
+end
diff --git a/lib/app_store_connect/request/body.rb b/lib/app_store_connect/request/body.rb
index b014ee5..7832abc 100644
--- a/lib/app_store_connect/request/body.rb
+++ b/lib/app_store_connect/request/body.rb
@@ -5,12 +5,22 @@ class Request
     class Body
       def self.inherited(klass)
         super
+
+        klass.include(Object::Included)
         klass.include(Object::Data)
       end
 
       def initialize(**kwargs)
+        @included = self.class::Included.new([*kwargs.delete(:included)])
         @data = self.class::Data.new(**kwargs)
       end
+
+      def to_h
+        {
+          data: data.to_h,
+          included: included.to_a
+        }
+      end
     end
   end
 end
diff --git a/spec/app_store_connect/request/body_spec.rb b/spec/app_store_connect/request/body_spec.rb
index 1659c90..b2dc22e 100644
--- a/spec/app_store_connect/request/body_spec.rb
+++ b/spec/app_store_connect/request/body_spec.rb
@@ -4,6 +4,7 @@
   let(:klass) do
     Class.new(described_class) do
       include AppStoreConnect::Object::Data
+      include AppStoreConnect::Object::Included
 
       data do
         attributes do
@@ -18,6 +19,6 @@
   subject { instance.to_h }
 
   describe '#to_h' do
-    it { is_expected.to eq({ data: { attributes: { bar: :baz } } }) }
+    it { is_expected.to eq({ included: [{ type: :foo }], data: { attributes: { bar: :baz } } }) }
   end
 end
diff --git a/spec/bundle_id_create_request_spec.rb b/spec/bundle_id_create_request_spec.rb
index d09802f..7ab58a7 100644
--- a/spec/bundle_id_create_request_spec.rb
+++ b/spec/bundle_id_create_request_spec.rb
@@ -17,7 +17,8 @@
               name: attributes.name,
               platform: attributes.platform
             }
-          }
+          },
+          included: []
         )
       end
     end
@@ -36,7 +37,8 @@
               seed_id: attributes.seed_id,
               platform: attributes.platform
             }
-          }
+          },
+          included: []
         )
       end
     end