Carson Shephard was last seen in the Afton Bridgend area of New Cumnock, some 40 miles south of Glasgow, at about 7.20pm on Sunday (September 19).
He is about 3ft 6ins, has short dark brown hair and is of slim build. He was last known to be wearing dark blue jeans, a t-shirt and a black top.
Since Carson was reported missing, the local community has also been helping officers in the area.
Police have urged the public to “check garden sheds, gardens, garages and not assume someone else” has already searched the areas.
Anyone who has any information or may have seen Carson, or know of his whereabouts, is asked to call Police Scotland on 101, or 999 in an emergency situation, quoting incident number 3162 of Sunday September 19.