Firefighters responded to a structure fire on Graham Street, Broadmeadows at 1.26am after callers to triple-zero (000) reported a house fire.
Fire Rescue Victoria (FRV) crews arrived on the scene within three minutes to find smoke and flames issuing from the roof of the weatherboard unit, so the response was escalated.
Firefighters donned breathing apparatus and began attacking the fire, preventing it from spreading to adjoining properties, which were quite close and affected.
One occupant evacuated safely and was assessed by Ambulance Victoria for smoke inhalation.
The fire in the 8-metre by 8-metre double-storey brick unit was deemed under control by 2am.
The cause of the fire is not yet known.
It will be investigated by FRV specialists.