The mishap occurred at around 12.30 pm near Gandhinagar junction when the bus with 35 passengers on-board was en-route to Powai, a senior police official said.
The driver might have lost control over wheels and rammed the bus into the divider alongside the road, after which it turned turtle, he added.
A passenger Imtiaz Shaikh died on the spot, while the injured were taken to a nearby public hospital, the officer said, adding a case has been registered at the Park Site police station.