The accused, identified as R C Prajapati, molested the 17-year-old girl yesterday at a hostel when its warden had gone out for some work, they said.
As per the complaint, the victim, a student of Government Girls Higher Secondary School, in Birsinghpur Pali village, returned to the hostel along with other girls at around 5.45 PM yesterday.
The accused allegedly molested her and threatened her with dire consequences if she informed about the offence to anybody, they said.
Superintendent of Police, Umaria, P S Uike said the principal has been arrested.
The accused has been booked under various sections of IPC and provisions of Protection of Children from Sexual Offences Act.