Toronto police say the 28-year-old male driver was killed after being thrown from his silver-coloured motorcycle and into a light pole.
"The motorcycle struck a curb and subsequently the rider struck the pole," said Const. Clint Stibbe.
A female passenger, 20, was also thrown from the bike and suffered life-threatening injuries. She's currently in hospital, police said.
The crash happened on a winding stretch of road in the Rosedale Valley. Witnesses told police speed may have been a factor.
Police cordoned off Rosedale Valley Road from Park Road to Bayview Avenue to investigate what caused the crash, but the roadway reopened around 6:30 a.m.