It broke out after 11:00 p.m. Wednesday at an apartment building in the 800 block of Main Street.
No injuries were reported, but 13 families, a total of 31 people, were forced to find other lodging.
Most went to stay with family or friends. The Red Cross assisted five of those families, providing shelter overnight at the Red Cross House in University City.
Red Cross representatives were set to meet with affected residents at 11:00 a.m. Thursday at the Darby Recreation Center, 1020 Ridge Avenue in Darby Borough.