The Chester County Sheriff's Office is asking the public for help finding 16-year-old Ethan Smart.
Smart went missing from the Edgemoor area.
The teenager, who has mental disabilities, was last seen on Mays Drive, the sheriff's office said on Saturday.
Smart is described as about 5'7" tall, weighing 120 pounds, with brown hair.
At the time of his disappearance, he was wearing a Carhartt hoodie underneath an army green jacket. Smart was also wearing jogging pants and black and white Vans shoes.
Law enforcement and fire personnel are conducting thorough searches of the area.
The sheriff's office assured the public there is no active threat at this time.
Officials are urging anyone with information about Smart's whereabouts to contact them immediately at 803-385-5433.