District Mahila Court Judge N Thirunavukkarasu sentenced Saravanan (31), Muthu Aliba (24) and Asiq Akram (27) to life imprisonment for raping the 17-year-old girl.
He also slapped a fine of Rs 20,000 on Saravanan and Rs 2,000 each on the others.
The prosecution case was that Saravanan, a vegetable vendor of Periya Agraharam here, saw the girl alone in her house on November 9 2014, went there with his two friends, kidnapped her, took her to an isolated house and raped her.
Police traced the missing girl in a house, following which the trio were arrested.