Estate disputes are increasingly common, where the passing of a family member results in surviving family members challenging the contents of the deceased’s Will. Estate litigation often arises when a surviving family member feels unfairly or improperly excluded as a beneficiary.

In Ontario, a person may challenge a Will in court if they have a financial interest in the deceased’s estate. Most Will challenges are brought by spouses, dependents, and adult children.

Grounds for challenging a Will

Courts will not invalidate a Will on the basis of vague allegations of unfairness or unhappiness by interested parties. Instead, judges apply the principle that a valid Will should stand and the deceased’s wishes should be respected.

The onus of proving a Will is invalid falls on the party bringing the challenge. This means that absent evidence to the contrary, a court will assume that the person who wrote a Will was fully competent and had the mental capacity to do so at the time the Will was made.

A Will in Ontario may be challenged on the following grounds:

Lack of capacity

A valid Will requires that the person making it (known as the testator) was aware and approved of everything written. A Will may be set aside as invalid if the testator did not have the capacity to comprehend its terms at the time it was made.

A testator’s capacity to make a valid Will may be in doubt if:

  • They didn’t understand the nature of the document that they were signing (i.e. that it is a Will and its effects);
  • They didn’t understand the extent of the matters covered within the Will;
  • They didn’t realize who was included or excluded as a beneficiary;
  • They misunderstood how the terms of their Will were likely to be interpreted under the law.

Note that not every misunderstanding on the part of a testator will render their Will invalid. The person challenging the Will must prove a causal connection between the misunderstanding and the challenged clause (e.g. the disinheritance of a beneficiary).

Undue influence

Barring evidence to the contrary, a court will assume that a Will reflects the genuine wishes of the testator. 

Where there is evidence that some outside influence may have coerced the testator into doing something against their true wishes, the Will may be set aside.  Therefore, a successful challenge against a Will based on undue influence requires that the court be persuaded that someone other than the testator exercised some unfair or improper influence, cheating, fraud, or other coercive pressure. 

Improper execution

In Ontario, Wills must generally be executed in a prescribed manner set out under the Succession Law Reform Act. For example, they must be in writing and have two witnesses who have signed the Will with the testator present. A court may set aside a Will where the legal requirements for signing were not followed.


If evidence can be produced to show that all or part of a Will was based on falsified, forged or otherwise misleading documents, the affected parts (or entire Will) may be set aside.

Age or changed circumstances

In some cases, a Will may have been prepared a long time ago and is considered out of date because of significant life changes (e.g. a testator has another child after making their Will but fails to update the Will accordingly). A court may decide to set aside the Will in these circumstances because it no longer reflects the true wishes of the testator.


If a Will contains language that is so vague that the testator’s intentions cannot be determined with any degree of certainty, it may be invalidated on the basis of ambiguity.

Public policy considerations

In Ontario, the concept of testamentary freedom – i.e., the testator’s freedom to include whatever they want in their Will –  is not absolute. Where a court agrees that a Will offends public morality, it can set the Will aside. This is a complex area of the law, and there are no concrete rules, but some examples of cases where a court has set aside a Will due to public policy concerns include:

  • Bequests that are conditional on the beneficiary not getting married (or remarried);
  • Will clauses that implicitly or explicitly promote or encourage illegal conduct; and
  • Testamentary gifts that discriminate against prospective beneficiaries on the basis of their religion.

Will challenges usually begin by filing a Notice of Objection with the court. In the Notice, the objector (the person challenging the Will) details the reason for their objection and sets out their interest in the deceased’s estate.

When a Notice of Objection has been filed, a court will not process any application for a Certificate of Appointment of Estate Trustee until the objection is removed. As a result, the estate cannot be distributed until the objection has been dealt with. If a Certificate of Appointment has already been granted, the objecting party cannot proceed by Notice of Objection. Instead, they may bring a motion demanding the return of the Certificate to the court.


Generally, the unsuccessful party in an estate dispute such as a Will challenge will be ordered to pay at least some of the winner’s legal costs. However, recovering 100% of your costs is rare, and courts have broad discretion to apportion costs as they see fit. Judges can also impose costs on a party if they feel the WIll challenge was frivolous or a waste of court time and resources.

The value of an experienced estate litigation lawyer

Will challenges are legally complex and usually require parties to go to court. Many hearings may be needed throughout the process. For example, a motion may be necessary to obtain disclosure of the testator’s medical records to determine whether they had testamentary capacity when the Will was made.

Given the complicated nature of Will challenges, it is important to seek the advice of an experienced estate litigation lawyer. Being represented by knowledgeable legal counsel can avoid the time and cost of errors and unnecessary steps taken during the litigation process.

Contact Tierney Stauffer LLP in Ottawa, Cornwall, Arnprior, Kingston & North Bay for Skilled Estate Litigation Services

Tierney Stauffer LLP uses a client-focused approach and provides innovative guidance through the estate litigation process. Our estate lawyers provide practical and honest advice to clients and advocate for their interests in any legal forum, including litigationmediation, or arbitration. To schedule a confidential consultation with a member of our team, contact us online or call 1-888-799-8057.


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