The action, taken without comment from the justices, means the 90-year-old civil rights figure can go ahead with her lawsuit against the band.
The 1998 song is about the entertainment industry and its lyrics do not refer to Parks by name. The chorus of the song goes, "Ah-ha, hush that fuss. Everybody move to the back of the bus."
Parks claimed that OutKast violated her publicity and trademark rights and defamed her. She lost her first round in federal court, but a three-judge panel of the 6th U.S. Circuit Court of Appeals in Cincinnati reinstated part of the lawsuit earlier this year.
The case will now return to a lower federal court judge.
Parks wants all references to her removed from future versions of the record.
OutKast has argued that the song is neither false advertising nor a violation of Parks' publicity rights and is protected by the First Amendment.
Parks made history in December 1955 when she was arrested for refusing to give up her seat to a white man on a Montgomery, Ala., and city bus. Her arrest triggered a 381-day boycott of the bus system by blacks and led to court rulings desegregating public transportation nationwide.
The case is LaFace Records v. Parks, 03-504.