Can the seller back out of a deal while my conditions are still outstanding in Ontario?

Once a seller has accepted your offer — even if conditions remain outstanding — they are generally bound by the Agreement of Purchase and Sale and cannot simply accept another offer or walk away. The conditions are there for the buyer's benefit; they do not release the seller from their obligations.

There are narrow exceptions. Some agreements include a seller's "escape clause" or right of first refusal clause, which allows the seller to continue marketing the property and, if another offer comes in, to give the buyer notice to waive conditions within a short period (typically 24–48 hours). Without such a clause, the seller is bound until your condition period ends.

If a seller purports to back out of a binding deal without legal justification, the buyer may have remedies including a claim for damages or, in some circumstances, a claim for specific performance (a court order requiring the seller to complete the sale). These are contentious and expensive disputes to resolve, so it is worth speaking with a real estate lawyer immediately if you believe a seller is improperly walking away from an accepted offer.