Police said Khristian Joseph was last seen leaving Pleasant Grove Elementary School on foot at about 3:45 p.m.
Joseph is described as being black with black hair and dark brown eyes. He is about 4 feet, 9 inches tall and weighs about 90 pounds.
Authorities said he was last seen wearing an olive green jacket, dark blue jeans and black sneakers with neon green laces.
Authorities said Joseph doesn't ride the bus or walk home from school. He is usually picked up in front of the school by a relative.
An active search was underway Monday night and investigators were focusing on the area around the school and the woods behind it. Surveillance video showed Joseph walking from the school toward the woods, police said.
“At his point we have searched that area of the woods completely. We’ve gone all the way through the woods from the school all the way over to Page Road to [Interstate] 540 and to pretty much the entire area surrounding the school. Inside the school we’ve searched several times,” Capt. Kevin Tingen said.
Authorities said they would remain on the scene overnight.
Authorities said Joseph does have a cell phone but he did not have it with him Monday because his mother had recently taken it away.
Police said K9 and fire department personnel were assisting in the search.
Anybody with information is asked to call Cary police at 919-469-4012.