Bailey Townend, 16, was last seen in the town two weeks ago on Wednesday, April 17, at around 10.15pm.
Despite extensive enquiries, North Yorkshire Police say they have been unable to find the youngster and are growing increasingly concerned for his welfare.
They are now appealing to the public for information on his whereabouts.
Bailey is described as white, around 5ft 6ins tall, of average build with brown hair and blue eyes.
It is believed he may still be in the Harrogate area.
Anyone who thinks they may have seen Bailey or has information on his whereabouts is asked to contact North Yorkshire Police via 101, with reference 12190069622.