She was in a precarious condition at a Bandra hospital and was on ventilator.
"The victim died early this morning," Namdev Chavan, Zonal Deputy Commissioner of police told reporters here.
The girl was admitted to the Gurunanak hospital since December 22 after she was inflicted multiple knife injuries by Nikhil Bankar, with whom she was said to have broken up.
Bankar(22) had also repeatedly stabbed himself and died from self-inflicted wounds at the time of admission to a hospital.
Both were studying management at Chetna College.
According to police, Bankar had accosted the girl and three of her friends while they were on their way to the classroom in the morning of December 22.
Following a heated argument, Nikhil whipped out a knife from his bag and slashed her several times.
He then stabbed himself 4-5 times and also slashed his throat.