Alexander Lakatos, who is also known as Alex, was last seen in Malsis Road at about 8am on 23 May.
He is described as white, of medium build and about 5ft 9ins tall with short black hair.
He was last seen wearing a dark blue tracksuit and white trainers.
He is believed to still be in the Keighley area, but is also known to frequent Bradford.
Officers are continuing enquiries to locate him and any sightings should be reported to police in Bradford on 101, quoting log 656 of 23 May.