Liam Johnson was last seen at his home in Suffolk on Saturday, July 23, and officers are growing increasingly concerned for his welfare.
Officers believe he is likely to be in Northamptonshire, in particular Rushden or Wellingborough.
However, Liam is also believed to have been visiting or spending time with friends or family in High Wycombe, Buckinghamshire.
Liam is white, 5ft 6in, with short, blonde hair, a slim build and blue eyes.
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He was last seen wearing a blue T-shirt, a black hoodie, faded blue tracksuit bottoms and navy blue trainers.
Officers are urging Liam or anyone who believes they may have seen him or has any idea of his whereabouts, to call Northamptonshire Police on 101.
Alternatively, please call Crimestoppers anonymously on 0800 555111.