Shaun Harrison, 16, has been missing since Thursday, February 22 and officers today said they are concerned for his welfare.
He had been living in Middlesborough and came back to Hull on that date. He was last seen in Hull city centre.
Mr Harrison is white, 5ft 6ins, stocky, with short ginger hair. He was wearing a blue Nike cap, blue hooded jacket, dark jogging bottoms with green/grey trainers.
He has links to the east Hull area. It is thought Mr Harrison does not have any money on him.
A spokesperson for Humberside Police said: "Despite our efforts to locate him we have been unable to.
"There have been reports that Shaun has been seen around Hull since but we need to confirm that he is safe."
Call 101 with information, citing log 324 of February 22.