The incident took place at Karhakol village in Ekauna area.
The girl, who was in love with one Ranjit, was asked by the village panchayat and the youth's family members to sever ties with him but she ignored their order and remained in touch with the boy.
Irked over her defiance, four villagers today barged into her house, sprinkled kerosene on her and set her on fire, SP Umesh Kumar Srivastav said.
She was rushed to a nearby hospital with 80 per cent burn injuries and her condition was stated to be serious.
Police have filed an FIR against four in this connection and also arrested two of them.