Three other people in the home suffered non-life threatening injuries, the Bay Area News Group reported Friday.
Police said the dead girl, Alaysha Carradine, was inside a 7-year-old friend's residence in the city's Dimond district when someone rang the doorbell shortly after 11 p.m. Wednesday.
Shots were fired when Alaysha's friend opened the door. Bullets pierced the apartment's metal gate and hit Alaysha, her friend, the friend's 4-year-old brother and their 64-year-old grandmother.
Police have not determined a motive for the shootings.
Alaysha is youngest of the 54 people killed in the city of Oakland so far this year.