Molly Osswald, 17, was last seen leaving home on Jan. 28 and has not been seen since.
Police believe she is still in the Treasure Valley, but searches have failed to locate her.
She is described as 5 feet tall, 115 pounds. She has sandy hair and brown eyes.
Anyone with information on Osswald's whereabouts is asked to call Mark Payne, the police department's school resource officer, at 888-6678.