diff --git a/lib/active_model/array_serializer.rb b/lib/active_model/array_serializer.rb
index ad5ce346..b3e67aa5 100644
--- a/lib/active_model/array_serializer.rb
+++ b/lib/active_model/array_serializer.rb
@@ -20,16 +20,13 @@ module ActiveModel
       @meta            = options[@meta_key]
       @each_serializer = options[:each_serializer]
       @resource_name   = options[:resource_name]
-      @key_format      = options[:key_format]
+      @key_format      = options[:key_format] || options[:each_serializer].try(:key_format)
     end
     attr_accessor :object, :scope, :root, :meta_key, :meta, :key_format
 
     def json_key
-      if root.nil?
-        @resource_name
-      else
-        root
-      end
+      key = root.nil? ? @resource_name : root
+      key_format == :lower_camel ? key.camelize(:lower) : key
     end
 
     def serializer_for(item)
diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index a2c832f9..f0244a6e 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -117,14 +117,16 @@ end
       @except        = Array(options[:except]) if options[:except]
       @key_format    = options[:key_format]
     end
-    attr_accessor :object, :scope, :root, :meta_key, :meta
+    attr_accessor :object, :scope, :root, :meta_key, :meta, :key_format
 
     def json_key
-      if root == true || root.nil?
+      key = if root == true || root.nil?
         self.class.root_name
       else
         root
       end
+
+      key_format == :lower_camel ? key.camelize(:lower) : key
     end
 
     def attributes
diff --git a/test/fixtures/poro.rb b/test/fixtures/poro.rb
index 6909ef2c..a357c24e 100644
--- a/test/fixtures/poro.rb
+++ b/test/fixtures/poro.rb
@@ -35,7 +35,7 @@ end
 class Comment < Model
 end
 
-class Blog < Model
+class WebLog < Model
 end
 
 ###
@@ -66,10 +66,10 @@ class CommentSerializer < ActiveModel::Serializer
   attributes :content
 end
 
-class BlogSerializer < ActiveModel::Serializer
+class WebLogSerializer < ActiveModel::Serializer
   attributes :name, :display_name
 end
 
-class BlogLowerCamelSerializer < BlogSerializer
+class WebLogLowerCamelSerializer < WebLogSerializer
   format_keys :lower_camel
 end
diff --git a/test/integration/action_controller/serialization_test.rb b/test/integration/action_controller/serialization_test.rb
index 7ffd4c56..9065e211 100644
--- a/test/integration/action_controller/serialization_test.rb
+++ b/test/integration/action_controller/serialization_test.rb
@@ -194,6 +194,22 @@ module ActionController
       end
     end
 
+    class LowerCamelArraySerializerTest < ActionController::TestCase
+      class WebLogController < ActionController::Base
+        def render_array
+          render json: [WebLog.new({name: 'Name 1', display_name: 'Display Name 1'}), WebLog.new({name: 'Name 2', display_name: 'Display Name 2'})], each_serializer: WebLogLowerCamelSerializer
+        end
+      end
+
+      tests WebLogController
+
+      def test_render_array
+        get :render_array
+        assert_equal 'application/json', @response.content_type
+        assert_equal '{"webLog":[{"name":"Name 1","displayName":"Display Name 1"},{"name":"Name 2","displayName":"Display Name 2"}]}', @response.body
+      end
+    end
+
     class ArrayEmbedingSerializerTest < ActionController::TestCase
       def setup
         super
diff --git a/test/unit/active_model/array_serializer/key_format_test.rb b/test/unit/active_model/array_serializer/key_format_test.rb
index 6ddd82b8..4c247bfd 100644
--- a/test/unit/active_model/array_serializer/key_format_test.rb
+++ b/test/unit/active_model/array_serializer/key_format_test.rb
@@ -4,8 +4,8 @@ module ActiveModel
   class ArraySerializer
     class KeyFormatTest < Minitest::Test
       def test_array_serializer_pass_options_to_items_serializers
-        array = [Blog.new({ name: 'Name 1', display_name: 'Display Name 1'}),
-                 Blog.new({ name: 'Name 2', display_name: 'Display Name 2'})]
+        array = [WebLog.new({ name: 'Name 1', display_name: 'Display Name 1'}),
+                 WebLog.new({ name: 'Name 2', display_name: 'Display Name 2'})]
         serializer = ArraySerializer.new(array, key_format: :lower_camel)
 
         expected = [{ name: 'Name 1', displayName: 'Display Name 1' },
diff --git a/test/unit/active_model/serializer/key_format_test.rb b/test/unit/active_model/serializer/key_format_test.rb
index aada664a..135866bf 100644
--- a/test/unit/active_model/serializer/key_format_test.rb
+++ b/test/unit/active_model/serializer/key_format_test.rb
@@ -4,8 +4,8 @@ module ActiveModel
   class Serializer
     class KeyFormatTest < Minitest::Test
       def test_lower_camel_format_option
-        object     = Blog.new({ name: 'Name 1', display_name: 'Display Name 1'})
-        serializer = BlogSerializer.new(object, key_format: :lower_camel)
+        object     = WebLog.new({ name: 'Name 1', display_name: 'Display Name 1'})
+        serializer = WebLogSerializer.new(object, key_format: :lower_camel)
 
         expected = { name: 'Name 1', displayName: 'Display Name 1' }
 
@@ -13,8 +13,8 @@ module ActiveModel
       end
 
       def test_lower_camel_format_serializer
-        object     = Blog.new({ name: 'Name 1', display_name: 'Display Name 1'})
-        serializer = BlogLowerCamelSerializer.new(object)
+        object     = WebLog.new({ name: 'Name 1', display_name: 'Display Name 1'})
+        serializer = WebLogLowerCamelSerializer.new(object)
 
         expected = { name: 'Name 1', displayName: 'Display Name 1' }