The City’s Fire and Rescue Service received the emergency call at 1:40 and crews from Epping, Belhar and Gugulethu were dispatched to the scene of the fire in Oliehout Road.
Firefighters found two structures engulfed in flames and managed to contain and extinguish the fire.
The bodies of a woman and two boys were discovered under the debris, while one woman and a boy were treated for burn wounds and transported to a nearby hospital.
The cause of the blaze is unknown and the scene was handed over to the South African Police Service.