Flames shot through the roof of a Walker Avenue townhouse complex in Orillia.
The lone male occupant was able to flee the residence unharmed, though fire crews say several people were treated for smoke inhalation.
First responders were called out to the blaze on Monday afternoon, and the fire was contained to a single unit.
Firefighters from Rama also assisted.
The cause of the fire is under investigation.
Banner image – @OrilliaFire