R. Dorothy Wayneright (the "R." presumably stands for "Robot", a prefix coined by Isaac Asimov for his robots) is a female android or more properly a gynoid from the anime series Big O. She is modeled after Dr. Wayneright's late daughter Dorothy.

Dorothy appears at first glance to be human but possesses the expected strength, agility, and intelligence of an android. Her body parts sometimes make mechanical sounds, with little inflection in her face or voice. However, she seems to possess emotions (and has smiled on occasion) in particular a clever sarcasm when speaking with Roger, usually about his shortcomings.

Dorothy lives with Roger, and a running joke among the fans - due to Dorothy's apparent 'age' and nonhumanity - was the precise nature of their relationship, which was later alluded to in the series.