Jody Hockett vanished on Feb. 22, 2009, after being seen getting into a small white car outside a Grande Prairie hotel.
Police say they believe there are people who know something about what happened to Hockett, but have chosen not to come forward.
They say some of those people were in her social circle when she disappeared.
Hockett, who would now be 37, was described at the time as being five-foot-five and 140 pounds, with blue eyes and long blond hair.
Investigators are asking anyone who might have information to call the Grande Prairie RCMP detachment.