Briana Villegas, 14, was last seen Friday at 6:30 p.m. She may be in Sunnyvale with family.
Briana is 5 feet 2 inches tall, 100 pounds with brown hair and brown eyes, according to police. She was last seen wearing black bicycle shorts and a black shirt with the letters "OMI" on it.
Police said Briana is in good physical and mental condition.
Anyone with information about the girl can call the Police Department's missing persons unit at (510) 238-3641.