Jeanette Genge may be heading to Montreal, police said.
She is described as an English-speaking white girl with brown, shoulder-length hair and glasses. She stands at about five feet five inches tall and weighs about 145 pounds.
Genge was dressed in black with black makeup.
She was last seen leaving her west-end home at about 9:30 a.m. Tuesday, police said.
Police did not release a photo.
Anyone with information is asked to call the missing persons unit at 613-236-1222, ext. 2352 or 2353, or Crime Stoppers at 613-233-8477 (TIPS) — toll free at 1-800-222-8477.