Gunfire was reported just before 4 p.m. at Fig/Oleander Park, according to the Los Angeles County Sheriff's Department.
Compton's fire department said the victim was a 12-year-old boy who had been shot in the stomach.
First responders performed a blood-transfusion on-site before rushing the boy to a hospital, according to the fire department. The boy was later pronounced dead at the hospital.
A description of the shooter was not immediately available. Authorities did not release further details about the shooting.