The shooting occurred about 1:30 a.m. in the 12100 block of Sheldon Street, where the woman approached the building on foot and fired multiple rounds, according to the Los Angeles Police Department.
The shooter then fled the scene and the boy was transported to a hospital with a leg wound, an LAPD sergeant said. He is expected to recover.
No other injuries were reported.
A detailed description of the woman, who remained at large, was not immediately available.