The girl was returning home late last night after helping out in a feast for the poor, organised by AIADMK cadres on the occasion of former Chief Minister Jayalalithaa's 67th birthday on Tuesday.
Her friend, who was accompanying her, took her to a secluded spot and raped her, unaware that three other persons were in the area, police said, adding, then they too allegedly raped her.
Police said investigations are on to ascertain if the four accused were relatives of the AIADMK functionaries.
Police did not reveal the girl's age.