The Westchester County district attorney's office says John Azabache pleaded guilty Tuesday to third-degree rape for having sex with a 16-year-old student.
His lawyer, Tony Castro, says Azabache will be sentenced in December to 10 years of probation and will have to register as a sex offender.
Azabache, of Port Chester, was a math teacher at Ossining High. He was arrested in July when police said he'd had sex twice with the girl.
His planned July 12 wedding was canceled and his ex-fiancee obtained an order of protection.
The school district says Azabache has off the payroll since last week.