Jason Adutwum was first reported missing at around 9.30pm on Friday 17th December.
Thames Valley Police say they are still appealing for help to find 15-year-old Jason.
He is approximately 5ft 6ins tall, of a slim build, with brown hair and brown eyes.
He was last seen wearing a black top, black trousers, a black jacket and white trainers.
Jason is known to have links to Bedfordshire, London, Norfolk, Northamptonshire and Surrey.
Detective Inspector Gemma Robinson, based at Milton Keynes police station, said: “We are becoming increasingly concerned for Jason’s welfare and are appealing for help in locating him.
“Please get in touch with us if you have seen Jason or think you know where he may be.
“You can report information by calling 101, quoting reference 43210569379.”