Can my co-owner force me to sell our Ontario property if I don't want to?

In most cases, yes. Ontario's Partition Act gives any co-owner the right to apply to the Superior Court of Justice for partition (physical division of the land) or sale of the property. If partition is not practical — which it usually is not for a house or condo — the court can order the property sold and the proceeds split according to each party's ownership interest.

Courts have discretion to refuse a partition or sale in limited circumstances, such as where an order would be oppressive, where there is a valid co-ownership agreement restricting it, or where the applicant has acted in bad faith. But the threshold for refusal is high, and a co-owner who simply does not want to sell is unlikely to succeed in blocking the application indefinitely.

The best protection against an unwanted forced sale is a co-ownership agreement entered into before or at the time of purchase. Such an agreement can include a right of first refusal — obliging the departing co-owner to offer their share to you first at a set price before applying to court — and a hold period during which neither party can apply for partition without consent.

If you receive a court application for partition, you should contact a lawyer immediately, as the timelines are strict.