A blaze erupted on Monday afternoon at a home on Carlisle Parade in the New Lodge area, prompting emergency services to respond rapidly to prevent further spread.
Four fire appliances and one aerial appliance were dispatched to the scene when alarms sounded at 4.44pm.
Firefighters arrived to find flames consuming an upper floor of the building, with the risk of ignition moving to adjacent properties imminent.
Local residents played a critical role in the early response, managing to guide a neighbour out of the house before it became too dangerous to remain inside.
Those who assisted also sounded the alarm among other occupants along the Carlisle Parade terrace, ensuring wider notification of the emergency.
Three individuals were injured during the incident but are understood to be suffering non-life threatening conditions.
The victims received immediate care at a residence belonging to another local resident while firefighters worked to extinguish the blaze.
The cause of the fire remains unconfirmed as investigators continue their work on Monday afternoon.