Can more than one party be considered an occupier responsible for the same property in Ontario?

Yes. The Occupiers' Liability Act explicitly allows more than one party to be considered an occupier of the same property at the same time, since "occupier" is defined by actual control rather than by ownership, and control over different aspects of one property can genuinely be split between several parties simultaneously. An owner, a tenant, a property manager, and a maintenance contractor could each qualify as an occupier with respect to different parts, or different aspects, of the very same premises, depending on their specific roles.

Each occupier's duty is then assessed based on the degree of control they actually had over the specific condition that caused the injury, so a court can find multiple parties liable together for the same incident, or find that only the party with genuine control over the relevant hazard actually bears responsibility, even though others technically also qualify as occupiers in some general sense. This is part of why identifying every party with any meaningful control over a property - not just the obvious owner - is a routine and important early step in these kinds of claims.