Family members say Janet Choi was last seen Saturday morning walking to an art class in Koreatown, but she never made it to the class.
Choi is a senior at Fairfax High School and lives with her mother. Family and friends say her disappearance is unusual.
"She is not like this. She never caused a problem in school and when her mother contacted the school today, they were shocked because she is a model student and never even had a problem whatsoever at school," said John Kang, a family friend.
Her mother says her phone has been turned off. Choi has black hair, brown eyes, is 5 feet 3 inches and weighs about 90 pounds.
If you have any information on her whereabouts, you are urged to call Los Angeles police at (877) LAPD-24-7.