Christopher Metcalfe, 70, from Blidworth, Nottinghamshire, is accused of five historical sex offences against three girls in the 1970s and '80s.
The woman, now in her 40s, was 15 when she was attacked by Mr Metcalfe, a rural studies teacher at Skegby Hall, near Mansfield, jurors heard.
Mr Metcalfe has denied all charges at Derby Crown Court.
The alleged victim said Mr Metcalfe had taken her to his house, thrown her to the floor and ripped her clothes before starting to rape her.
She said she tried to run away from him but could not get to the door.
The assault ended about 10 minutes later when a young man, believed to be Mr Metcalfe's son, arrived home, the court heard.
The defence suggested the woman had made up the allegation to try to win a compensation pay-out, but she denied this.
Mr Metcalfe is also accused of raping another teenage girl at his home as well as indecently assaulting a nine or 10-year-old girl during "story-time" and after a swimming lesson.
The trial continues.
A woman who accuses a teacher of raping her while she was in care has denied making up the allegation for money.