Kieran Kirk, from Cupar, was last seen around 12.40am on Friday (June 17) in the Strathden area.
Police said they are growing increasingly concerned for his welfare.
Kieran is described as 5ft 11ins, medium build, with long, light brown hair, which is scruffy.
He was last seen wearing all dark clothing, and black boots with screws on the front.
Extensive enquiries are ongoing to trace Kieran, who has been known to travel considerable distances and camp out for extended periods of times.
He has previously been traced in Cumbria and Suffolk.
Sergeant Andy Kirk said “We are growing increasingly concerned for Kieran and it is important we trace him as soon as possible to ensure he is safe and well.
“If anyone has seen him or knows where he might be then please contact us 101, quoting reference number 0308 of Friday, 17 June, 2022.”