Packirisamy, the headmaster of the school in Sethur village was arrested last night based on a complaint by the five-year old girl's parents.
On the evening of August 18, the child returned from school feeling unwell and when her parents enquired what happened, she told them about the teacher's assault.
The parents approached the school management the next day, but after the school administrator reportedly did not initiate any action, they lodged a complaint with the police, who, after an inquiry, arrested Packirisamy.
Alleging that the school administrator was also involved in the incident and demanding his arrest, the parents along with several other residents of the village last night staged a protest.
The Superintendent of Police of Karaikal (North) Marimuthu and other officials held talks with the agitating people and assured action following which they dispersed, police said adding further investigation is being carried out.