Can You Challenge a Will After Probate in Ontario?

Many people assume that once a will has gone through probate, it's beyond question — final, settled, and closed. That's not accurate. Challenging a will after probate in Ontario is genuinely harder than doing so before a grant is issued, but the grant itself does not put the will's validity beyond legal reach.

Understanding what probate actually confirms, and what it doesn't, is the key to understanding why a post-probate challenge is still possible, and what it takes to bring one.

The Common Misconception

Probate, formally a Certificate of Appointment of Estate Trustee, is often assumed to mean a court has carefully reviewed and approved the will's validity the way it would in a contested hearing. In reality, an uncontested probate application is largely administrative: it confirms that the estate trustee has authority to act, based on the documents filed. It is not the same as a court adjudicating a dispute between interested parties about whether the will is actually valid.

What Probate Actually Confirms

A grant of probate confirms that, based on the materials submitted, the applicant appears entitled to act as estate trustee under the will presented. It does not mean every beneficiary or family member has already had a chance to raise concerns, and it does not immunize the will from every future legal argument.

Why a Post-Probate Challenge Is Harder — But Not Impossible

Challenging a will after a grant has already issued generally requires asking the court to revoke or vary the existing certificate, in addition to proving one of the recognized grounds for invalidity:

• Lack of testamentary capacity
• Lack of knowledge and approval of the will's contents
• Undue influence
• Fraud
• Failure to meet formal signing and witnessing requirements

The substantive grounds don't change after probate — what changes is the practical and procedural burden. Assets may already have started moving, other parties have relied on the grant, and the court will generally expect a clear explanation for why the challenge wasn't raised earlier, where that's relevant to the facts.

Timing Matters More Once Probate Has Been Granted

Ontario's general two-year limitation period applies to many civil claims, including estate-related ones, and the clock can be tied to when a claim was, or reasonably should have been, discovered. Separately, a dependant's support claim under the SLRA is generally subject to a six-month deadline running from the grant of probate or administration, though a court has some discretion to allow a later claim against any part of the estate that hasn't yet been distributed. Neither deadline pauses simply because a grant has already been issued — if anything, they make prompt advice more important once a grant is in place.

Steps to Take If You Believe a Grant Was Wrongly Issued

1. Get the underlying documents. Request a copy of the will and the probate application materials to understand exactly what was filed and on what basis.
2. Identify your specific ground. Determine whether your concern fits one of the recognized grounds — capacity, knowledge and approval, undue influence, fraud, or execution formalities.
3. Act quickly. Given the limitation periods involved, delay works against you in almost every scenario.
4. Get legal advice before assets move further. The more of the estate that has already been distributed, the more complicated recovery becomes, even with a strong claim.

Frequently asked questions