The Class 12th student, one of the beneficiaries of the free laptop distribution scheme of the Akhilesh Yadav government, was returning from the function at a degree college around midnight.
Police said the girl, like many other girls from a school at Shukul Bazaar, went to the event but got delayed as the Social Welfare Minister Avdhesh Prasda, the chief guest at the function, arrived at 10 p.m. instead of the scheduled 3 p.m.
When the girls got their laptops around 10.30 p.m., they rushed back home in the jeep which had taken them to the function.
The jeep's owner, Sunil Kumar Singh of Vishambharpatti village, dropped other girls and later took the vehicle to an isolated place and raped the girl.
He then dumped her outside the village and fled. The girl narrated the harrowing tale to her family who approached the police.
"We have lodged an FIR and are on the lookout for the culprit," a police official told IANS.
Meanwhile, the villagers are angry at the minister and blame his late arrival at the event for the incident.