Toronto Fire Services was called to a house in South Riverdale just before 6:00 p.m. on Saturday evening.
Crews arrived at 14 McGee Street near Eastern Avenue to find flames shooting out the roof and upgraded the situation to a second alarm fire.
It is unclear how many people were inside the house at the time of the fire, but no injuries were reported.
Road closures are in effect in the area while crews battle the blaze.
Toronto Fire Services says they are making good progress on the house and that most of the flames have been put out.
The extent of the damage is currently unknown.
