Headmaster Jagdish Prasad and teachers Narendra Garg and Sanjay Kumar allegedly sexually abused the girls, about a fortnight ago, they said.
The girls, who are all 7 years old, study in class 2 of Government Middle School, they said.
After the incident, the girls stopped going to school and informed their mothers about it.
The parents then approached the school administration, but were driven out by the staffers, police said.
A case under Protection of Child From Sexual Offence Act (POCSO) has been registered against the three, the police said, adding that no one had been arrested so far.
Meanwhile, people of 'Devasion-ki-Dhani' village, from where the girls hail, today held a protest demanding arrest of the accused, police said.