diff --git a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
index fa1dbfdf06..34859617c9 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
@@ -32,7 +32,7 @@ class Class
   def cattr_reader(*syms)
     options = syms.extract_options!
     syms.each do |sym|
-      raise NameError.new('invalid attribute name') unless sym =~ /^[_A-Za-z]\w*$/
+      raise NameError.new("invalid class attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
         unless defined? @@#{sym}
           @@#{sym} = nil
@@ -93,7 +93,7 @@ class Class
   def cattr_writer(*syms)
     options = syms.extract_options!
     syms.each do |sym|
-      raise NameError.new('invalid attribute name') unless sym =~ /^[_A-Za-z]\w*$/
+      raise NameError.new("invalid class attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
         unless defined? @@#{sym}
           @@#{sym} = nil
diff --git a/activesupport/test/core_ext/class/attribute_accessor_test.rb b/activesupport/test/core_ext/class/attribute_accessor_test.rb
index 8d827f054e..0d5f39a72b 100644
--- a/activesupport/test/core_ext/class/attribute_accessor_test.rb
+++ b/activesupport/test/core_ext/class/attribute_accessor_test.rb
@@ -44,16 +44,18 @@ class ClassAttributeAccessorTest < ActiveSupport::TestCase
   end
 
   def test_should_raise_name_error_if_attribute_name_is_invalid
-    assert_raises NameError do
+    exception = assert_raises NameError do
       Class.new do
-        cattr_reader "invalid attribute name"
+        cattr_reader "1nvalid"
       end
     end
+    assert_equal "invalid class attribute name: 1nvalid", exception.message
 
-    assert_raises NameError do
+    exception = assert_raises NameError do
       Class.new do
-        cattr_writer "invalid attribute name"
+        cattr_writer "1nvalid"
       end
     end
+    assert_equal "invalid class attribute name: 1nvalid", exception.message
   end
 end