Kalaivani of Selvapuram locality consumed poison in her house and was rushed to hospital in the wee hours but she died without responding to treatment, police said.
She was dejected last evening when she returned from college.
Preliminary investigations revealed that Kalaivani was asked by a teacher to write answers to some questions on the blackboard. As she wrote wrong answers, her classmates made fun of her, police said.
The student's family alleged that the teacher was instrumental in her suicide and demanded action.