Does a will dispute settlement reached at mediation need court approval to be binding in Ontario?

Generally, a settlement reached at mediation between capable adult parties is binding on its own once it's properly documented and signed, without needing a judge to approve it, in the same way most civil settlements don't require court sign-off. The parties simply carry out the terms — for example, by consenting to a specific distribution or a particular person acting as estate trustee — and the litigation is resolved on those terms.

Court approval becomes necessary, though, where the settlement affects someone who cannot legally bind themselves to it — most importantly, a minor beneficiary or a beneficiary who is legally incapable. In those situations, a settlement isn't enforceable against that person's interest simply because their litigation guardian or the Office of the Children's Lawyer agreed to it at the table; it needs to be brought before a judge, who reviews whether the settlement is actually in that person's best interests before approving it. The same is generally true where the Public Guardian and Trustee is involved on behalf of an incapable adult. Anyone negotiating a settlement involving a minor or incapable beneficiary should build the time and cost of this approval step into their expectations from the outset.