What happens if more than one person files a Notice of Objection to the same will in Ontario?

Nothing prevents more than one interested person from filing a separate Notice of Objection against the same will, and it isn't unusual in a family dispute where several beneficiaries or potential heirs share similar concerns about capacity, undue influence, or a later will. Each objection is recorded against the estate, and the registrar will not issue a certificate of appointment based on that will while any of them remains outstanding.

Where the objections raise overlapping or related issues, the court can consolidate them into a single proceeding, or at least manage them together through case conferences, so the estate isn't forced to respond to duplicate litigation over essentially the same question. This is generally more efficient for everyone, including the objecting parties, since it avoids inconsistent findings and duplicated legal costs. Where the objections raise genuinely different grounds, they may still need to be addressed somewhat separately, though a court will usually try to deal with the will's validity as a whole rather than piecemeal. Anyone joining an existing dispute as a second or third objector should get advice on how their position fits with the others, since coordinating usually serves everyone's interests, including cost management.