Deputies say at least two gunmen walked up the door of the Northern California home and fired at least a dozen shots.
Elvira Campos was killed. Her parents were also wounded by the gunfire but were expected to survive. Their names have not been released.
The girl's 14-year-old brother was in the house at the time of the shooting but not injured.
"Whoever these gunmen were, they were directly outside the front door," Sacramento County sheriff's spokesman Sgt. Jason Ramos said Sunday. "This was not a drive-by. These gunmen approached the house and shot inside."
Investigators believe the shooting was gang-related and may have been tied to another family member.
Deputies responded to a separate shooting nearby the 10-year-old victim's home Sunday. The victim of that shooting was a 32-year-old suspected gang member. Detectives were looking at the possibility that both shootings were related.
The Associated Press contributed to this report.