Crews were called to the Croyden Station Apartments in the 900 block of Bristol Pike in the B Building around 11:00 p.m.
The fire was placed under control within 20 minutes.
No injuries were reported in the blaze.
The American Red Cross Southeastern Pennsylvania assisted 13 families, 33 people with financial assistance for food, clothing, and lodging.
In all, 25 apartments were affected.
The Red Cross says several other families had other places to go and did not need assistance. They will likely be able to return to their apartments in the next few days.
There is no word yet on a cause.