Can I sue my landlord if I am injured due to unsafe conditions in my rental unit in Ontario?

Yes. A landlord who controls common areas, or who is responsible for maintaining the structure and systems of a rental property, can be liable under the Occupiers' Liability Act if unsafe conditions they knew or should have known about caused your injury - a broken stair, faulty wiring, inadequate lighting in a stairwell, or a hazard you reported that was never fixed. Liability generally depends on which specific areas and repairs fell to the landlord versus which fell to the tenant under the lease, and on whether the landlord had reasonable notice of the problem along with a reasonable opportunity to fix it before you were hurt.

Your own conduct can also be relevant to the outcome if it contributed to the injury in some way. Because so much of these claims turns on what the landlord actually knew and when, keeping a clear record of maintenance requests - dates, how the request was made, and how or whether the landlord responded - is usually the single most valuable piece of evidence a tenant can have if a hazard eventually causes an injury.