Can I take over the seller's commercial lease when I buy a business in Ontario?

Often yes, but you usually need the landlord's consent. This matters most when your business depends on its location. If a lease has a covenant against assigning, subletting or parting with possession without consent, the lease is deemed to say consent is not to be unreasonably withheld.

That protection does not apply where the lease expressly provides otherwise. If the landlord refuses or neglects to consent, the tenant, the assignee or the subtenant can apply to a judge of the Superior Court of Justice, who decides whether consent was unreasonably withheld and can order the assignment permitted, which then counts as the landlord's consent.

Whether a refusal or condition is unreasonable depends on the facts. The lease itself decides other points that matter to a buyer, such as the remaining term, renewal rights, and whether the seller or a guarantor stays responsible after an assignment. Because your location may be the heart of the business, read the lease and ask the landlord before you commit to the purchase, and have a lawyer review it. Ideally, make your purchase depend on getting the landlord's consent in writing.