Can the outcome of a capacity assessment be appealed or reviewed in Ontario?

There isn't a formal, standalone appeal process for a capacity assessment result the way there is for a court decision, but that doesn't mean the finding is beyond question. Where an assessment leads to a statutory guardianship of property, mechanisms exist to have the finding reviewed, including seeking a further assessment addressing whether incapacity remains, or applying to court in connection with the guardianship itself. Where an assessment is being used as evidence in a court proceeding, such as a contested guardianship application, its conclusions can be challenged directly within that proceeding through cross-examination, competing expert evidence, or a second opinion.

Because there's no single, simple review process, the right way to challenge a specific assessment depends heavily on what legal process the assessment is connected to and what outcome you're trying to change. Simply disagreeing with the result isn't enough on its own — an effective challenge generally requires substantive evidence questioning the assessor's methodology, the information they relied on, or the person's actual functioning. Get legal advice promptly to identify the right review or challenge mechanism for your specific situation, since timing can affect what options remain available.