The girl, employed as domestic help, lives with her younger brother in a suburban shanty, the Bandra police said.
The victim had spurned marriage proposal of one of the accused. Today, at about 1 am, five persons abducted her in a vehicle and took her to a slum in Mankhurd, they said.
Three of the five accused raped the girl taking turns, police said, adding the accused threatened to kill her if she revealed the incident to police.
"A gangrape case has been registered and a manhunt has been launched to nab the accused. The victim has undergone a medical test. She is in a stable condition," senior police inspector Ramchandra Dhawale said.