What role does the Public Guardian and Trustee play in an Ontario will validity dispute?

The Public Guardian and Trustee can become involved in an Ontario will validity dispute where a beneficiary or potential heir is a legally incapable adult with no one else appropriate to represent their interests, or where the estate itself has no other suitable person willing to act. As with the Office of the Children's Lawyer for minors, an estate trustee or another party is generally expected to give notice to the Public Guardian and Trustee where an incapable person's financial interest is affected by the litigation, so their office can decide whether to step in.

Where the Public Guardian and Trustee does participate, it acts to protect that incapable person's interests specifically — reviewing the evidence, taking positions on the will's validity as it affects that person's share, and, where relevant, deciding whether a proposed settlement genuinely serves that person's best interests before it can bind them. It does not automatically take over the whole case or act for every party. Because involving the Public Guardian and Trustee (or failing to, when required) can affect whether a resolution is valid and enforceable, get advice early in any dispute involving an incapable beneficiary about whether and how to give the required notice.