diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index 953d24a3b2..3caa61e41b 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -71,8 +71,8 @@ module ActiveModel
   #   BookCover.model_name        # => "BookCover"
   #   BookCover.model_name.human  # => "Book cover"
   #
-  #   BookCover.model_name.i18n_key              # => "book_cover"
-  #   BookModule::BookCover.model_name.i18n_key  # => "book_module.book_cover"
+  #   BookCover.model_name.i18n_key              # => :book_cover
+  #   BookModule::BookCover.model_name.i18n_key  # => :"book_module/book_cover"
   #
   # Providing the functionality that ActiveModel::Naming provides in your object
   # is required to pass the Active Model Lint test. So either extending the provided
diff --git a/activemodel/test/cases/naming_test.rb b/activemodel/test/cases/naming_test.rb
index e8db73ba52..b2976ab1fb 100644
--- a/activemodel/test/cases/naming_test.rb
+++ b/activemodel/test/cases/naming_test.rb
@@ -34,6 +34,10 @@ class NamingTest < ActiveModel::TestCase
   def test_human
     assert_equal 'Track back', @model_name.human
   end
+
+  def test_i18n_key
+    assert_equal :"post/track_back", @model_name.i18n_key
+  end
 end
 
 class NamingWithNamespacedModelInIsolatedNamespaceTest < ActiveModel::TestCase
@@ -74,6 +78,10 @@ class NamingWithNamespacedModelInIsolatedNamespaceTest < ActiveModel::TestCase
   def test_param_key
     assert_equal 'post', @model_name.param_key
   end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
 end
 
 class NamingWithNamespacedModelInSharedNamespaceTest < ActiveModel::TestCase
@@ -114,6 +122,10 @@ class NamingWithNamespacedModelInSharedNamespaceTest < ActiveModel::TestCase
   def test_param_key
     assert_equal 'blog_post', @model_name.param_key
   end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
 end
 
 class NamingWithSuppliedModelNameTest < ActiveModel::TestCase
@@ -154,6 +166,10 @@ class NamingWithSuppliedModelNameTest < ActiveModel::TestCase
   def test_param_key
     assert_equal 'article', @model_name.param_key
   end
+
+  def test_i18n_key
+    assert_equal :"article", @model_name.i18n_key
+  end
 end
 
 class NamingUsingRelativeModelNameTest < ActiveModel::TestCase
@@ -188,6 +204,10 @@ class NamingUsingRelativeModelNameTest < ActiveModel::TestCase
   def test_param_key
     assert_equal 'post', @model_name.param_key
   end
+
+  def test_i18n_key
+    assert_equal :"blog/post", @model_name.i18n_key
+  end
 end
 
 class NamingHelpersTest < Test::Unit::TestCase