Sgt. James Long of the sheriff's Temple Station said the robbery happened just after 9 p.m. on Peck Road, north of Longden Avenue and west of Myrtle Avenue. The area lies in the unincorporated county area near Monrovia.
He said the robbers didn't have weapons, but he thinks they threatened the teen.
The suspects, described only as Latinos, were in a gray older model Honda Civic. The car was last seen northbound on Peck Road, according to Long.