October 21, 2025
Disputes over a deceased person’s estate can be emotionally and legally complex. In Ontario, individuals may contest a will if they believe it does not reflect the true intentions of the testator (the person who made the will) or if certain legal requirements were not met. But not everyone can challenge a will, and not every dispute will be successful.
Here’s a breakdown of when, how, and why someone might contest a will in Ontario—and what limitations they should keep in mind.
Who Can Contest a Will?
Generally, only those with a financial interest in the estate have legal standing to contest a will. This includes:
- Beneficiaries named in the will,
- Individuals who would inherit if there were no will (i.e., intestate heirs), and
- Persons who were named in a prior version of the will but left out of the final version.
Legal Grounds for Contesting a Will in Ontario
Ontario courts will not set aside a valid will simply because someone is unhappy with its contents. There must be a recognized legal ground for challenging the will. Common grounds include:
- Lack of Testamentary Capacity
The testator must have had the mental capacity to understand:
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- The nature of making a will,
- The extent of their assets, and
- Who their natural beneficiaries would be.
Evidence from doctors, caregivers, or others who knew the testator’s mental state at the time of execution can be crucial.
- Undue Influence
If someone exerted pressure on the testator to make or change a will in a way that doesn’t reflect the testator’s true wishes, a court may invalidate the will. This often arises in cases involving elderly or vulnerable individuals and a dominant caregiver or relative.
- Lack of Knowledge or Approval
Even if the testator signed the will, a challenge may succeed if they didn’t understand or approve its contents—especially if someone who stood to benefit played a role in the preparation of the will, such as picking the lawyer, making the appointment, or attending with the testator.
- Improper Execution
Ontario’s Succession Law Reform Act usually requires certain formalities for a will to be valid:
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- It must be in writing,
- Signed by the testator at the end, and
- Witnessed by two people who are not beneficiaries.
Failure to follow these rules may render a will invalid unless it qualifies as a valid holograph (handwritten) will.
- Fraud or Forgery
If a will was forged or the testator was misled into signing it under false pretenses, it can be invalidated.
When to File a Will Challenge
Timing matters. In Ontario, will challenges are best be brought before probate is granted. Once a Certificate of Appointment of Estate Trustee is issued, it becomes more difficult to halt the administration of the estate.
If probate has already been granted, a challenger must move quickly to bring a court application and seek a stay of estate distribution.
What Happens During a Will Challenge?
Will contests are usually resolved through litigation or negotiated settlement. The process often involves:
- A court application,
- Disclosure of medical and legal records,
- Examination of witnesses (e.g., the drafting lawyer, witnesses to the will),
- Expert testimony on capacity (where applicable), and
- Mediation, which is mandatory in some jurisdictions like Toronto and Ottawa, but not in Thunder Bay or Northwestern Ontario.
The court will ultimately decide whether the will—or specific provisions within it—are valid or should be set aside.
Costs and Risks
Contesting a will is expensive, time-consuming, and emotionally draining. While Ontario courts may order the estate to pay legal costs in some circumstances, they are increasingly willing to make unsuccessful challengers pay out of pocket—especially if the challenge was speculative or vindictive.
Takeaways:
- Will challenges are serious legal undertakings.
- They are best avoided by having a will prepared by a lawyer who practices wills and estates law.
- If you suspect a will does not reflect the testator’s true intentions, or was executed under suspicious circumstances, you should act quickly and consult an estate litigation lawyer.
- The earlier concerns are raised, the greater the chance they can be resolved without years of costly litigation.
How Weilers LLP can help you
Our wills and estate lawyers know how to watch for undue influence or lack of capacity. We pride ourselves on drafting wills that withstand challenges.
In the event of a challenge, our estate litigation lawyers are proud of their record of success at reasonable cost.
For all your wills and estates needs, including will contests, give us a call. We may be the right lawyers for you.