User blog comment:Sunslicer2/She Was Working in a Bridal Shoppe.../@comment-1264520-20110220023502

Niles' last name is never revealed in the series, so it is unknown to the viewer if he has one. He claimed that his family name is 'Niles', "... like Cher.". CC Babcock guessed once that his last name was "DeButler".