Halton Regional Police say the collision occurred shortly after 1 a.m. Sunday, on Fifth Line, just south of Britannia Road.
Police say that a Pontiac Grand Prix was heading south when its driver, an 18-year-old male, lost control of the vehicle.
The Grand Prix overturned and hit a hydro pole. It came to rest on a field on the west side of Fifth Line.
A 17-year-old male was pronounced dead at the scene. The driver and two females were taken to hospital, where they are in serious, but stable condition, police say.
The collision remains under investigation. Anyone with information is asked to contact investigators at 905-825-4747, ext. 5065.