Vaughn Hirst, 15, left his home in Goole on Saturday.
Police said he was last seen in Snaith, East Yorkshire, earlier this evening but neither his family nor officers have managed to make contact with him.
He last returned to his home yesterday to collect some belongings. However, he did not provide details of where he was staying and concerns for his wellbeing are growing, as he has never been missing before and his behaviour is out of character.
Vaughn is said to have links to both Snaith and Halifax, West Yorkshire.
He is described as white, around 5ft 4in, of medium build, with short blond hair.
He was last seen wearing a black, blue and green Adidas shell suit top and dark jogging bottoms, with Nike trainers.
Anyone with information is asked to call 101, quoting log number 304 of June 29.