It was first reported shortly before 3 am Friday on Sierra Madre near Vagedes, just behind the San Joaquin Suites Hotel on Shaw Avenue.
Crews believe the fire may have sparked from a car inside the detached garage, but that is just a preliminary theory.
Officials say the garage is a complete loss, but the apartments are okay.
About eight units were evacuated, and crews had to cut power to the apartments.
Once electricity is restored, residents can return to the units.