The crime was allegedly committed in the house of one of the youths at nearby Dandupalya Hoskote, police said.
The girl in her complaint filed on April 18 with police alleged that the youths had kidnapped her, taken her to the house, forced her to consume alcohol and assaulted and gangraped her on Sunday last.
Police identified those arrested as Srikanth Nair and Vimod Venugopal (both from Alappuzha) and Nitin N Verghese, a native of Kerala and a resident of Dandupalya. They were arrested in that state.
All of them were booked under Section 376 of IPC (punishment for rape) and produced before a magistrate on the night of April 24.
Also Read
The three knew the woman and misused their familiarity with her to get to come to the house, sexually assaulted her and robbed her of her money and gold ring, a police release said.
Police said they are investigating the "mystery woman" the victim had mentioned in her complaint. The student had said the woman gave her clothes to wear and later dropped her off at St John's hospital.