The Academy of Motion Picture Arts and Sciences says the 42-year-old filmmaker submitted his resignation Tuesday, one day after he apologized for using a gay slur at a screening of his latest movie.
Academy President Tom Sherak says Ratner "did the right thing for the academy and for himself."
Sherak says, "Brett is a good person, but his comments were unacceptable."
Ratner was named Oscar producer in August along with TV veteran Don Mischer.
Ratner issued an open letter Tuesday explaining his resignation.