Toronto Fire Services were called to a row of houses on Oxford Street, near Spadina, around 1 a.m. ET and found the rear of a home fully engulfed in flames. The blaze then spread to the roof and attic, eventually reaching three adjacent properties.
All residents of the homes safely escaped injury, though firefighters did say some family pets were likely lost.
The Toronto Fire Marshal is on scene and investigating the possible causes of the fire.
Spadina Avenue was closed to traffic and streetcars for several hours as firefighters battled the blaze, but has now reopened.