diff --git a/railties/lib/rails/generators.rb b/railties/lib/rails/generators.rb
index 76ef598d68719..1f1813dcad48d 100644
--- a/railties/lib/rails/generators.rb
+++ b/railties/lib/rails/generators.rb
@@ -158,7 +158,7 @@ def self.find_by_namespace(name, base=nil, context=nil) #:nodoc:
     # commands.
     def self.invoke(namespace, args=ARGV, config={})
       names = namespace.to_s.split(':')
-      if klass = find_by_namespace(names.pop, names.shift)
+      if klass = find_by_namespace(names.pop, names.any? && names.join(':'))
         args << "--help" if args.empty? && klass.arguments.any? { |a| a.required? }
         klass.start(args, config)
       else
diff --git a/railties/test/generators_test.rb b/railties/test/generators_test.rb
index 214a69a949100..f902557d68c5c 100644
--- a/railties/test/generators_test.rb
+++ b/railties/test/generators_test.rb
@@ -94,6 +94,14 @@ def test_find_by_namespace_show_warning_if_generator_cant_be_loaded
     assert_match /Rails 2\.x generator/, output
   end
 
+  def test_invoke_with_nested_namespaces
+    model_generator = mock('ModelGenerator') do
+      expects(:start).with(["Account"], {})
+    end
+    Rails::Generators.expects(:find_by_namespace).with('namespace', 'my:awesome').returns(model_generator)
+    Rails::Generators.invoke 'my:awesome:namespace', ["Account"]
+  end
+
   def test_rails_generators_help_with_builtin_information
     output = capture(:stdout){ Rails::Generators.help }
     assert_match /Rails:/, output