Kian Byrne was reported missing on Thursday and was last seen at about 11.10pm in the Undercliffe area of the city.
Officers now say they are concerned for the welfare of the 17-year-old, who has links to Manchester and Leeds.
Detective Sergeant Steve Wedge of Bradford District CID, said: “We do have concerns for Kian’s welfare and are conducting a number of enquiries to locate him.
“He is believed to still be in the Bradford area and I would ask anyone who sees him or has information about his whereabouts to contact Bradford CID."
Kian is described as white, 5ft 10ins tall, and was last seen wearing grey tracksuit bottoms and a grey top, with a black coat and Nike trainers.
Anyone with information is asked to contact police on 101, referencing police log 1895 of March 1.