diff --git a/lib/generators/simple_form/templates/simple_form.rb b/lib/generators/simple_form/templates/simple_form.rb
index ab7f954f..075f6772 100644
--- a/lib/generators/simple_form/templates/simple_form.rb
+++ b/lib/generators/simple_form/templates/simple_form.rb
@@ -24,7 +24,7 @@ SimpleForm.setup do |config|
   # config.wrapper_class = :input
 
   # CSS class to add to the wrapper if the field has errors.
-  # config.wrapper_error_class = :fieldWithErrors
+  # config.wrapper_error_class = :field_with_errors
 
   # How the label text should be generated altogether with the required text.
   # config.label_text = lambda { |label, required| "#{required} #{label}" }
diff --git a/lib/simple_form.rb b/lib/simple_form.rb
index d62e7cf7..0d53f0ae 100644
--- a/lib/simple_form.rb
+++ b/lib/simple_form.rb
@@ -48,7 +48,7 @@ module SimpleForm
 
   # You can define the class to add to the wrapper when the field has errors. Default is fieldWithErrors.
   mattr_accessor :wrapper_error_class
-  @@wrapper_error_class = :fieldWithErrors
+  @@wrapper_error_class = :field_with_errors
 
   # How the label text should be generated altogether with the required text.
   mattr_accessor :label_text
diff --git a/test/components/wrapper_test.rb b/test/components/wrapper_test.rb
index f0ddcfd4..afa542f6 100644
--- a/test/components/wrapper_test.rb
+++ b/test/components/wrapper_test.rb
@@ -16,17 +16,17 @@ class WrapperTest < ActionView::TestCase
 
   test 'wrapper should not have error class for attribute without errors' do
     with_error_for @user, :active
-    assert_no_select 'div.fieldWithErrors'
+    assert_no_select 'div.field_with_errors'
   end
 
   test 'wrapper should not have error class when object is not present' do
     with_error_for :project, :name
-    assert_no_select 'div.fieldWithErrors'
+    assert_no_select 'div.field_with_errors'
   end
 
   test 'wrapper should add error class for attribute with errors' do
     with_error_for @user, :name
-    assert_select 'div.fieldWithErrors'
+    assert_select 'div.field_with_errors'
   end
 
   test 'wrapper should add chosen error class for attribute with errors' do
diff --git a/test/form_builder_test.rb b/test/form_builder_test.rb
index 936f66b0..1649dff3 100644
--- a/test/form_builder_test.rb
+++ b/test/form_builder_test.rb
@@ -305,7 +305,7 @@ class FormBuilderTest < ActionView::TestCase
 
   test 'builder wrapping tag adds errors class for attribute with errors' do
     with_form_for @user, :name
-    assert_select 'form div.input.required.string.fieldWithErrors'
+    assert_select 'form div.input.required.string.field_with_errors'
   end
 
   # WITHOUT OBJECT