The blaze started just before midnight on Thursday in the three-story structure that has a store in the front.
The building's on the 800 block of Main Street in Darby Borough.
When firefighters got the 911 call they were told some people were trapped in the fire.
But by the time crews arrived everyone managed to get out of the building safely.
There are no reports of any injuries.
It took 20 minutes for firefighters to knock down the flames.
Investigators are searching for the cause.