Toronto police responded to reports of a three-vehicle crash in the area of Jane Street and Weston Road around 11:36 p.m.
Upon arrival, emergency responders found several people with various injuries.
A woman in her 20s was taken to a trauma center via emergency with serious, non-life-threatening injuries, Toronto paramedics said.
Four other people were taken to hospital with minor injuries.
The cause of the collision is unknown.
Police are asking any witnesses to contact them at 416-808-1900.