Contesting a Will in Ontario: Grounds, Deadlines and Costs

A family member dies. The will surfaces. And something feels wrong. Maybe the person who stood to gain the most was the one who “helped” arrange the paperwork. Maybe the will was signed weeks before death when the testator could barely recall their grandchildren’s names. At Mardini Law, we hear from families in exactly this position regularly: uncertain whether their suspicion is legally actionable or just grief looking for a target.

Contesting a will in Ontario is a serious legal process with defined rules, strict deadlines, and real financial stakes. This article walks you through who can challenge a will in Ontario, what grounds courts actually accept, what evidence you need, how the process works, and what it realistically costs. By the end, you’ll know whether your situation warrants a legal challenge and what your next move should be.

Who can actually contest a will in Ontario

Not everyone who dislikes a will has the legal right to challenge it. Ontario courts require a challenger to have “standing,” which means a genuine financial interest that would be affected depending on whether the will is upheld or set aside. This is the first filter, and it matters before you spend a dollar on legal fees. The main categories of people who qualify include:

• Beneficiaries named in an earlier will who would receive more if the current one fails
• Heirs who would inherit under Ontario’s intestacy rules if no valid will exists
• Beneficiaries named in the current will whose share may shift

Separately, certain dependants can bring a support claim under Part V of the Succession Law Reform Act. That claim does not attack the will at all. It asks the court to order adequate support from the estate even if the will is perfectly valid, and it has its own deadline, discussed below.

Being a close friend, a longtime caregiver, or someone who simply “expected” to be included does not create standing on its own. Standing only gets you in the door. Courts then ask whether you can point to a recognized legal ground for invalidity. Having a financial interest doesn’t mean the will gets thrown out, it means you’re entitled to raise the question. That distinction matters enormously when you’re weighing whether to proceed.

The legal grounds Ontario courts recognize when contesting a will

Lack of testamentary capacity

Lack of testamentary capacity is the most commonly argued ground. At the time of signing, the testator must have understood they were making a will, the general nature and extent of their property, and the people with a natural claim on their estate. They must also have been free from a mental disorder that distorted those decisions. A diagnosis of dementia alone doesn’t automatically establish incapacity. Ontario courts assess the evidence from the specific time instructions were given and the will was executed.

Undue influence

Undue influence is a separate ground, and courts treat it distinctly. It requires proof that someone’s coercion or manipulation actually replaced the testator’s independent judgment, causing the will to reflect the influencer’s wishes rather than the testator’s own. Mere persuasion, even persistent persuasion, isn’t enough. The bar is real, and clearing it requires concrete evidence of control, isolation, or threats.

Fraud, forgery, and execution defects

The remaining grounds cover fraud and forgery, deliberate misrepresentation, and failure to follow Ontario’s execution formalities. Under Ontario law, a formal, witnessed will must be written, signed by the testator at its end, and signed by at least two witnesses present at the same time. Witnessing by video is permitted where at least one witness is a licensee of the Law Society of Ontario. A holograph will, written entirely in the testator’s own handwriting and signed by them, needs no witnesses at all. A deviation from the formalities can open a challenge, but it is no longer necessarily fatal: since 2022, section 21.1 of the Succession Law Reform Act allows the court to give effect to a document that sets out the deceased’s testamentary intentions even if it was not properly executed.

Suspicious circumstances

Separate from these grounds, courts look closely at suspicious circumstances. This is not a ground of invalidity on its own. It is an evidentiary doctrine that changes who has to prove what. Examples include a sudden unexplained change benefiting the person who arranged the will, an isolated or vulnerable testator, or instructions that arrived through an interested party rather than the testator directly. When suspicious circumstances exist, the usual presumption that the testator knew and approved of the will’s contents (and, where it is in question, had capacity) falls away, and the burden shifts to the person relying on the will to prove knowledge and approval, and capacity where it is in issue, on a balance of probabilities. The burden of proving undue influence or fraud does not shift. It remains with the person alleging it.

What evidence you actually need to proceed

Ontario courts apply a screening threshold before requiring the person relying on a will to prove it formally, and before compelling production of records. The challenger must point to real evidence that, if accepted, could call the will’s validity into question. The standard is an “air of reality,” not full proof. Bare allegations and dissatisfaction with the inheritance won’t get you past the first gate.

The threshold traces back to the Court of Appeal’s decision in Neuberger v. York, 2016 ONCA 191, and was framed as a “minimal evidentiary threshold” in Seepa v. Seepa, 2017 ONSC 5368. Courts require an actual evidentiary foundation supporting the allegations, not assertions taken at face value. What that looks like in practice depends on the ground you’re arguing:

• Capacity challenges: contemporaneous medical records, hospital or long-term-care charts with nurses’ notes, family physician or geriatrician observations near the signing date, medication records, and the drafting lawyer’s notes are the most persuasive materials. Courts look for first-hand clinical observations recorded close in time to when instructions were given.
• Undue influence: evidence of isolation, dependency, the alleged influencer’s control over the testator’s access to information, their involvement in giving instructions, and any sudden unexplained change in the will’s distribution.
• Suspicious circumstances or fraud: evidence of deception, concealment, or an unusual pattern in how the will was prepared or executed.

What courts routinely dismiss at the preliminary stage is worth knowing clearly. “He always said he’d leave everything equally” without supporting documentation, generalized family disagreements about fairness, and assumptions based solely on the testator’s age or illness don’t meet the threshold. Once the threshold is met, courts can order production of medical, financial, and solicitor-file records. Failing to meet it ends the challenge early, often with a costs order against the challenger.

Key deadlines for contesting a will in Ontario

Timing is critical in Ontario will challenges, and two clocks matter.

The first is the limitation period. A will challenge is generally subject to the two-year limitation period under the Limitations Act, 2002, which courts have held usually runs from the date of death, subject to discoverability (see Leibel v. Leibel, 2014 ONSC 4516). Miss it and the claim may be barred however strong it is.

The second is procedural. Wherever possible, act before the Certificate of Appointment of Estate Trustee is issued. Once probate is granted, the Notice of Objection route is closed and you face a more complex motion to return the certificate, a harder and more expensive road.

The Notice of Objection is filed using Form 75.1 in the Superior Court of Justice, and a modest court filing fee applies. The form identifies your financial interest and the general nature of your objection. It is not a final challenge, it preserves your position and prevents the probate certificate from issuing while the dispute is resolved. An objection expires three years after it is filed, and the rule provides no way to renew it. Before the hearing for directions, the objector can withdraw it, and the court can order it removed.

Other claims have their own, shorter deadlines. A dependant’s support claim under Part V of the Succession Law Reform Act must generally be started within six months after the Certificate of Appointment is issued. A surviving married spouse who wants to elect an equalization of net family property under the Family Law Act, instead of taking under the will, must generally do so within six months of the death. Courts can extend some of these deadlines in limited circumstances, but no one should plan on it.

How the Notice of Objection process unfolds

After the estate applicant serves a Notice to Objector (Form 75.3), you have 20 days to serve and file a Notice of Appearance (Form 75.4). Missing that deadline allows probate to proceed as if no objection existed. Either side can then move for directions under Rule 75.06. If the applicant does not do so within 30 days after being served with the Notice of Appearance, the objector may bring the motion. The court then sets the litigation roadmap: issues, document production, examinations for discovery, mediation, and the path to a hearing.

Once that schedule is set, the process typically moves toward mediation within four to eight months of the initial objection, with settlement possible within six to 18 months. If mediation fails and the case goes to trial, expect a timeline of two to four years from the start of litigation.

Mediation vs. litigation: how the path you choose affects cost and outcome

Most Ontario estate disputes settle before trial. In Toronto, Ottawa and Essex County, mediation is mandatory in most contested estate proceedings under Rule 75.1 of the Rules of Civil Procedure. Litigation is expensive, slow, and unpredictable. Knowing when to negotiate and when to fight is often the difference between recovering a fair share of the estate and spending it on legal fees. Here’s a realistic picture of what contesting a will in Ontario costs at each stage:

• Early settlement through negotiation: approximately $5,000 to $15,000 in legal fees, plus modest disbursements
• Contested motions or mediation: commonly tens of thousands of dollars, plus mediator fees (a full-day estate mediation typically runs $3,600 to $7,500 or more in total costs before adding lawyer preparation time)
• Complex Superior Court trial: roughly $50,000 to $150,000 or more in legal fees, plus disbursements including medical records, expert reports, transcripts, and valuation evidence

Hourly rates for Ontario estate lawyers generally fall between $250 and $1,000, based on current market rates, depending on experience and the complexity of the file. Disbursements add substantially on top of that, and they’re often underestimated at the outset.

On costs after judgment, Ontario courts apply the “costs follow the event” principle in estate litigation, as in other civil cases. The losing party typically pays a partial-indemnity contribution toward the winning side’s fees, which works out to roughly 50 to 60 percent of actual legal costs. An unsuccessful challenge exposes you to your own fees plus a contribution toward the other side’s costs. Where a claim lacked proper evidentiary basis or the challenger acted unreasonably, courts can award substantial-indemnity costs, a meaningfully higher penalty.

There are exceptions. Where the deceased’s own conduct caused the dispute, or where there were reasonable grounds to question the will’s validity, a court may order some or all costs paid from the estate. Those exceptions are applied narrowly, so they should not be counted on when budgeting. A realistic budget must account for all three: your fees, disbursements, and potential adverse costs.

How Mardini Law helps families navigate estate disputes fairly

Knowing you have grounds is only half the equation. Executing the strategy properly, preserving evidence, meeting deadlines, deciding whether to mediate or litigate, and managing financial exposure throughout, is where legal representation makes the real difference.

Mardini Law works with beneficiaries from the moment suspicion arises, not just once a Notice of Objection has been filed. That means reviewing the factual record, assessing standing and grounds honestly, advising on whether the evidence threshold is likely met, and laying out a realistic cost-benefit picture before a client commits to anything. Many disputes that look like they’ll go to trial resolve through well-prepared negotiation, once both sides understand the evidentiary landscape.

For families whose disputes require litigation, Mardini Law represents beneficiaries through the full process: objections, motions for directions, examinations for discovery, mediation, and Superior Court proceedings. The goal is a fair resolution, reached as efficiently as the case allows. A free initial consultation is the first step toward understanding your position clearly.

What to do if something about the will doesn’t add up

Contesting a will in Ontario requires four things: standing, a legally recognized ground, concrete evidence, and timely action, ideally before probate is granted and always within the limitation period. The cost and outcome depend heavily on whether the case resolves through negotiation, mediation, or a full trial. An unfair-feeling will is not automatically invalid, but if the facts point to capacity issues, coercion, or procedural defects, a challenge may be entirely warranted.

The key is getting an honest legal assessment early, before deadlines pass or evidence disappears. Medical records get harder to obtain. Witnesses’ memories fade. The drafting lawyer’s file becomes more difficult to access. Time works against challengers who wait.

If you’re questioning a will and wondering whether your concerns have legal weight, speaking with an estate litigation lawyer sooner rather than later protects your options. Contact Mardini Law for a free consultation to assess your position before deadlines narrow your options.