Angelica Lopez, 17, and her daughter Enalina Hernandez are believed to have been taken against their will by 19-year-old Marcos Hernandez, police said.
Police responded to the 2700 block of Alvingroom Court in response to a report of an assault and kidnapping at 11:10 p.m. Wednesday.
Witnesses told arriving officers that the mother and daughter had been abducted at gunpoint by the girl's father.
Hernandez, who is considered armed and dangerous, could be in the Sacramento County area and is believed to be driving a silver 2006 Ford Focus, according to police.
He is described as Hispanic, 5 feet 8 inches tall and 185 pounds, with short black hair and brown eyes.
Lopez is described as Hispanic, 5 feet 4 inches tall and 120 pounds, with black hair and brown eyes.
Anyone who sees the car or suspect is asked to call 911 immediately.
Oakland police and Crime Stoppers are offering a reward of $10,000 for information leading to an arrest in the case.