Flames broke out around 1:15 a.m. Monday at the complex located on the 2400 block of North 50th Street in the city's Wynnefield section.
Officials say the fire was started in the third floor hallway.
Fire crews evacuated the building as a precaution. The flames were placed under control at 1:22 a.m..
There were no reported of injuries.
The fire remains under investigation.