Andrew Gosden's parents Glenys and Kevin, and elder sister Charlotte, will be attending their usual church today to say prayers for the schoolboy, who left the family home in Littlemoor Lane, Balby, on September 14, 2007.
Mr Gosden, of Doncaster, said there had been "very few" possible sightings and none confirmed since Andrew's disappearance, despite numerous media campaigns.
He said: "I have continued to pursue specific areas with appeals when one looks vaguely plausible, but not a thing has come out of it."
On the day he vanished Andrew, then 14, headed off to McAuley Catholic High School as usual.
But instead of going to school that day, he returned home, changed out of his uniform into his usual Goth-style clothes and withdrew 200 from his savings account, with which he bought a one-way train ticket to London.
The last confirmed sighting of Andrew is a grainy closed circuit TV image of him leaving King's Cross station.
Anyone with information on the teenager's whereabouts should call Doncaster Police on 01302 385146 or the Missing People Helpline on 0500 700700.