Gwent Police says officers are concerned about the safety and wellbeing of missing 13-year-old Michael Driver because of his age.
He was last seen at his home in Rogiet, near Chepstow in Monmouthshire, on Saturday 12 October.
Anyone who has seen him or has any information about his whereabouts is urged to ring 101 or Crimestoppers on 0800 555 111.
More top news
How a little boy from Magor inspired his village to become "Autism Aware"
Nath talks to ITV News about being diagnosed with a form of autism at 16 and how he is aspiring to be a musician.
The head of Glamorgan CCC hopes Cardiff will be awarded one of the new city-based teams in a new 20/20 competition to rival the IPL.