Ewan Corbett, 14, was last seen in the village of Fellbeck, between Ripon and Pateley Bridge, during the early evening of Sunday, March 17. He is believed to have left the house of his own accord and travelled to Harrogate.
Police in Harrogate are urging people to keep an eye out and report any sightings of him.
Ewan is described as white, around 5ft 7in, with a slim build, brown shaven hair and blue eyes. He was wearing a dark-coloured hooded-top and black tracksuit bottoms when last seen.
Inspector Andy Chapman, of North Yorkshire Police, said: “We are increasingly concerned for Ewan’s safety and wish to trace him urgently.
“We believe he may be seeking accommodation and that he does not have the means to fend for himself, particularly in view of current adverse weather conditions.
“Ewen has friends and contacts throughout North Yorkshire, but so far enquiries with people he may have contacted have been unsuccessful.” Contact North Yorkshire Police via 101.