The deceased, identified as Khushboo, was a fifth grader at the Marwari Hindi Pathasala, they said.
According to school authorities, the girl complained of some uneasiness after swallowing the tablet which might have got stuck in her throat. Khushboo was then rushed to a private hospital where she was declared dead.
Police said the school administration had distributed anthelementic (de-worming) tablets to other children as well.
However, the girl's relatives alleged that the school authorities gave her an expired tablet.
A case in this regard has been registered at Ramagopalpet police station.
District Collector Murtaza Rizvi has announced a compensation of Rs 1.5 lakh for the family of the deceased.