diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index c7889407..cabead2d 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -36,6 +36,16 @@ module ActiveModel
       end
 
       def has_one(*attrs)
+        associate(Association::HasOne, *attrs)
+      end
+
+      def has_many(*attrs)
+        associate(Association::HasMany, *attrs)
+      end
+
+      private
+
+      def associate(klass, *attrs)
         options = attrs.extract_options!
 
         attrs.each do |attr|
@@ -47,7 +57,7 @@ module ActiveModel
             end
           end
 
-          @_associations << Association::HasOne.new(attr, options)
+          @_associations << klass.new(attr, options)
         end
       end
     end
@@ -76,12 +86,20 @@ module ActiveModel
           hash[association.key] = serialize_ids association
         end
         if association.embed_objects?
-          associated_data = send(association.name)
-          hash[association.embedded_key] = association.build_serializer(associated_data).serializable_hash
+          hash[association.embedded_key] = serialize association
         end
       end
     end
 
+    def serialize(association)
+      associated_data = send(association.name)
+      if associated_data.respond_to?(:to_ary)
+        associated_data.map { |elem| association.build_serializer(elem).serializable_hash }
+      else
+        association.build_serializer(associated_data).serializable_hash
+      end
+    end
+
     def serialize_ids(association)
       associated_data = send(association.name)
       if associated_data.respond_to?(:to_ary)
diff --git a/lib/active_model/serializer/associations.rb b/lib/active_model/serializer/associations.rb
index e04ca09e..aab18b85 100644
--- a/lib/active_model/serializer/associations.rb
+++ b/lib/active_model/serializer/associations.rb
@@ -47,6 +47,16 @@ module ActiveModel
           name
         end
       end
+
+      class HasMany < Association
+        def key
+          "#{name.singularize}_ids"
+        end
+
+        def embedded_key
+          name
+        end
+      end
     end
   end
 end
diff --git a/test/fixtures/poro.rb b/test/fixtures/poro.rb
index 7f39f38c..e9d41da3 100644
--- a/test/fixtures/poro.rb
+++ b/test/fixtures/poro.rb
@@ -25,6 +25,15 @@ end
 class Profile < Model
 end
 
+class Post < Model
+  def comments
+    @comments ||= [Comment.new(content: 'C1'),
+                   Comment.new(content: 'C2')]
+  end
+end
+
+class Comment < Model
+end
 
 ###
 ## Serializers
@@ -43,3 +52,13 @@ class ProfileSerializer < ActiveModel::Serializer
 
   attributes :name, :description
 end
+
+class PostSerializer < ActiveModel::Serializer
+  attributes :title, :body
+
+  has_many :comments
+end
+
+class CommentSerializer < ActiveModel::Serializer
+  attributes :content
+end
diff --git a/test/unit/active_model/serializer/has_many_test.rb b/test/unit/active_model/serializer/has_many_test.rb
new file mode 100644
index 00000000..7dd05e50
--- /dev/null
+++ b/test/unit/active_model/serializer/has_many_test.rb
@@ -0,0 +1,63 @@
+require 'test_helper'
+require 'active_model/serializer'
+
+module ActiveModel
+  class Serializer
+    class HasManyTest < ActiveModel::TestCase
+      def setup
+        @post = Post.new({ title: 'Title 1', body: 'Body 1', date: '1/1/2000' })
+        @post_serializer = PostSerializer.new(@post)
+        @post_serializer.class._associations[0].include = false
+        @post_serializer.class._associations[0].embed = :ids
+      end
+
+      def test_associations_definition
+        associations = @post_serializer.class._associations
+
+        assert_equal 1, associations.length
+        assert_kind_of Association::HasMany, associations[0]
+        assert_equal 'comments', associations[0].name
+      end
+
+      def test_associations_embedding_ids_serialization_using_serializable_hash
+        assert_equal({
+          '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_serialization_using_as_json
+        assert_equal({
+          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }
+        }, @post_serializer.as_json)
+      end
+
+      def test_associations_embedding_objects_serialization_using_serializable_hash
+        @post_serializer.class._associations[0].embed = :objects
+        assert_equal({
+          'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+        }, @post_serializer.serializable_hash)
+      end
+
+      def test_associations_embedding_objects_serialization_using_as_json
+        @post_serializer.class._associations[0].embed = :objects
+        assert_equal({
+          'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+        }, @post_serializer.as_json)
+      end
+
+      def test_associations_embedding_ids_including_objects_serialization_using_serializable_hash
+        @post_serializer.class._associations[0].include = true
+        assert_equal({
+          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }, 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+        }, @post_serializer.serializable_hash)
+      end
+
+      def test_associations_embedding_ids_including_objects_serialization_using_as_json
+        @post_serializer.class._associations[0].include = true
+        assert_equal({
+          '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
+    end
+  end
+end