How Long Do You Have to Challenge a Will in Ontario?

Finding out a will does not say what you expected is unsettling enough without also worrying about whether it is too late to do anything about it. In Ontario, the answer depends on a limitation period that sounds simple on its face but has generated real disagreement among courts about exactly when, and even whether, it applies to every kind of will challenge.

This guide covers:

•  The general two-year limitation period that applies to most will challenges

•  How the clock actually starts running, and why that date is not always obvious

•  A separate, much shorter deadline for dependant support claims

•  A recent court decision that complicates the picture for challenges to a will’s validity

At a Glance

The Two-Year Limitation Period

Most claims in Ontario, including most will challenges, are governed by the basic two-year limitation period set out in section 4 of the Limitations Act, 2002. A claim generally must be brought within two years of the date it was discovered, meaning the date the claimant knew, or reasonably ought to have known, that they had a basis to challenge the will. Section 5 of the Act sets out the discoverability test in more detail, and courts have applied it to will challenges specifically in cases such as Leibel v. Leibel, which held that the two-year period runs from when the claimant has knowledge of the material facts giving rise to the claim.

In practice, courts often start from a presumption that a will “speaks from death,” meaning the limitation period is presumed to begin on the date the testator died, since that is typically when an interested party would learn of the will’s contents. This presumption is not absolute. Someone who did not learn they had been left out of a will, or that a later will existed, until well after the death may be able to argue the clock did not start running until they actually discovered that fact. Because this argument depends heavily on specific evidence about what a person knew and when, it is not something to assume will apply without a proper review of the timeline.

Will challenges themselves generally rest on one of a handful of recognized grounds. A claimant might argue the testator lacked the mental capacity to understand what they were signing, that someone exerted undue influence over the testator, that the will was not executed the way the law requires, or that the testator did not actually know and approve of the document’s contents. Suspicious circumstances surrounding how a will was prepared are not, on their own, a separate ground for a challenge, though they can affect how a court weighs the evidence supporting one of these established grounds. Understanding which ground actually applies to a given situation matters just as much as knowing the deadline, since the evidence needed to prove capacity issues looks very different from the evidence needed to prove undue influence.

A Much Shorter Deadline for Dependant Support Claims

Will challenges are not the only estate-related claim with a limitation period, and dependant support claims run on a notably tighter schedule. Under section 61 of the Succession Law Reform Act, an application for support as a dependant of the deceased generally must be filed within six months of the certificate of appointment of estate trustee being issued. This is a much shorter window than the two-year period for challenging a will’s validity, and it catches people off guard specifically because they are often focused on the will itself rather than a separate support claim running on its own clock.

The court retains some discretion to allow a late dependant support application, but only against any part of the estate that has not yet been distributed, and permission is not guaranteed simply because the six months have passed. Someone who believes they may have a dependant support claim, alongside or instead of a straightforward will challenge, generally cannot afford to wait and see how a will dispute unfolds before addressing that separate deadline. Speaking with an Estate litigation lawyer Mississauga families work with early enough to confirm which deadlines actually apply, rather than assuming one clock governs every possible claim, tends to prevent a viable claim from expiring unnoticed.

It is worth being clear that a will challenge and a dependant support claim are legally distinct, even though they often arise from the same family dispute and the same estate. A person could have a strong argument that they qualify as a dependant entitled to support, entirely separate from any question about whether the will itself is valid. Treating the two as one issue, or assuming that pursuing one automatically preserves the other, is a common and costly mistake given how differently their deadlines run.

A 2026 Ruling Complicates When the Clock Even Applies

For years, the two-year limitation period was treated as a settled starting point for any will challenge. A 2026 Ontario Superior Court decision, Roberts v. Cowie, has introduced a meaningful wrinkle. In that case, the court considered whether a challenge to the validity of a will is a “claim” caught by the Limitations Act at all, and drew a distinction between ordinary civil claims seeking compensation for a loss and probate proceedings, where the court is instead determining whether a document actually reflects the deceased’s true testamentary intentions. The court’s reasoning suggests that not every will challenge fits neatly into the limitations framework the way a personal injury or contract claim would.

This does not mean the two-year period no longer matters, and treating it as irrelevant based on one recent decision would be a mistake. What it does mean is that whether a specific challenge is subject to the limitation period, and if so, when the clock actually started, has become a more fact-specific and legally contested question than it was a few years ago. Firms such as Gill and Alter Law generally treat the two-year figure as the deadline to plan around while flagging, case by case, whether more recent case law might open a longer window for a particular challenge.

Summary

Ontario’s basic limitation period for will challenges is two years, generally presumed to run from the date of the testator’s death, though that presumption can be displaced by evidence of later discovery. Dependant support claims run on a much shorter six-month clock. Recent case law has added genuine uncertainty about whether the two-year period applies to every will validity challenge in the first place, making early legal advice more valuable than it used to be.

Key Takeaways

•  Most will challenges must be brought within two years of discovering the basis for the claim, generally presumed to run from the date of death.

•  Dependant support claims under the Succession Law Reform Act must generally be filed within six months of the certificate of appointment being issued, a far shorter deadline than the will challenge period.

•  A 2026 decision, Roberts v. Cowie, has raised a genuine question about whether the two-year limitation period even applies to certain will validity challenges, adding uncertainty that favours getting legal advice sooner rather than later.

Given how much depends on exactly which deadline applies and when it started running, treating any of these timelines as a rough guideline rather than a hard date is a risk most people cannot afford to take.

Frequently Asked Questions

How long do I have to challenge a will in Ontario?

Most will challenges must be brought within two years under the Limitations Act, 2002, generally presumed to run from the date of the testator’s death unless evidence shows the claimant discovered the basis for the challenge later.

What is the deadline for a dependant support claim?

Dependant support claims under section 61 of the Succession Law Reform Act generally must be filed within six months of the certificate of appointment of estate trustee being issued.

Can the two-year deadline for a will challenge be extended?

The clock can start later than the date of death if a claimant can show they did not discover the basis for their challenge until afterward, but this depends on specific evidence and is not something to assume applies automatically.

What did Roberts v. Cowie decide about will challenges?

The 2026 decision considered whether a challenge to a will’s validity counts as a “claim” under the Limitations Act at all, distinguishing it from an ordinary civil claim for compensation. It has introduced real uncertainty about whether the two-year period applies the same way to every type of will challenge.

Is there an outer limit even if I discover a claim late?

Yes. The Limitations Act sets an ultimate 15-year limit that applies regardless of when a claim was discovered, though most will challenges are resolved well within that window under the standard two-year rule.

What happens if I miss the deadline to challenge a will?

If a court finds the applicable limitation period has expired and no exception applies, the challenge will generally be barred, meaning the will stands regardless of the challenge’s underlying merits.