diff --git a/lib/active_model_serializers.rb b/lib/active_model_serializers.rb
index 18679652..55cca1f1 100644
--- a/lib/active_model_serializers.rb
+++ b/lib/active_model_serializers.rb
@@ -3,6 +3,7 @@ require "active_support/core_ext/string/inflections"
 require "active_support/notifications"
 require "active_model"
 require "active_model/serializer"
+require "set"
 
 if defined?(Rails)
   module ActiveModel
@@ -63,6 +64,7 @@ module ActiveModel::ArraySerializerSupport
 end
 
 Array.send(:include, ActiveModel::ArraySerializerSupport)
+Set.send(:include, ActiveModel::ArraySerializerSupport)
 
 ActiveSupport.on_load(:active_record) do
   ActiveRecord::Relation.send(:include, ActiveModel::ArraySerializerSupport)
diff --git a/test/serializer_test.rb b/test/serializer_test.rb
index b785e3b6..86206158 100644
--- a/test/serializer_test.rb
+++ b/test/serializer_test.rb
@@ -434,6 +434,22 @@ class SerializerTest < ActiveModel::TestCase
     ], serializer.as_json)
   end
 
+  def test_sets_can_be_serialized
+    post1 = Post.new(:title => "Post1", :author => "Author1", :id => 1)
+    post2 = Post.new(:title => "Post2", :author => "Author2", :id => 2)
+
+    set = Set.new
+    set << post1
+    set << post2
+
+    serializer = set.active_model_serializer.new set, :each_serializer => CustomPostSerializer
+
+    assert_equal([
+      { :title => "Post1" },
+      { :title => "Post2" }
+    ], serializer.as_json)
+  end
+
   class CustomBlog < Blog
     attr_accessor :public_posts, :public_user
   end