Katie Hong, 16, was described as 5-foot with brown eyes, medium length dark brown hair and braces.
She was wearing a navy-blue zip-up jacket, grey sweatpants, and carrying a red Patagonia backpack.
Hong was last seen on Friday at about 6:20 p.m. on Queens Court.
She is considered at-risk, according to police.
Anyone who sees her was asked to call the Fremont Police Department at (510) 790-6800 or call 911 if the situation is an emergency.
Source: NBC Bay Area