The fire was reported at 6:42 p.m. Saturday in the 2100 block of Palos Verdes Drive North. Due to heavy smoke and large flames, it was escalated to a second-alarm fire, then a third-alarm was called around 8:30 p.m.
It took 150 firefighters nearly four hours to extinguish the flames.
Video from the scene showed heavy flames and smoke coming from the roof of the building.
It's unclear how many people had to be evacuated but no injuries were reported. The apartment building borders the Green Hills Memorial Park Cemetery.
The cause of the fire was being investigated.
City News Service, Inc. contributed to this report.