Court records show 20-year-old Mariah Yeater faces a bench trial Dec. 12 on a misdemeanor battery charge that could get her six months in jail and a $1,000 fine.
A police report says Yeater slapped her 18-year-old ex-boyfriend Dec. 21, 2010. The two were arguing about a window broken on the car of his new girlfriend.
The case was first reported by TMZ.
Yeater's lawyer in the battery case, John Spilotro, says she pleaded not guilty, and he declined to comment further.
Yeater attended school in Las Vegas before withdrawing from 10th grade in 2008.
She is suing the 17-year-old Bieber in California, seeking a paternity test and child support.