Yes, a will can be challenged in Ontario, but being excluded from the will or receiving less than expected is not, by itself, enough. A successful will challenge normally requires evidence of a recognized legal defect affecting the validity of the will — such as lack of testamentary capacity, undue influence, lack of knowledge and approval, improper execution, fraud, forgery, or other suspicious circumstances.

Ontario law starts from the principle that a person generally has the freedom to decide how their property will be distributed after death. A court does not rewrite a valid will simply because a beneficiary believes the result is unfair. The central question is whether the document truly represents the deceased’s valid testamentary intentions.

ME Law’s Estate Litigation practice addresses disputes involving wills, estates, executors, beneficiaries, and contested estate administration.

What are the main grounds for challenging a will?

1. Lack of testamentary capacity

The person making the will — the testator — must have had the mental capacity required to make a valid will when it was executed.

A capacity challenge may arise where there is evidence of cognitive decline, dementia, serious illness, medication effects, confusion, or another condition that calls into question whether the testator understood the nature of making a will, the property being disposed of, and the claims of those who might reasonably expect to benefit.

Capacity is assessed in the factual context surrounding the making of the will. Medical records, lawyer’s notes, witness evidence, prior wills, and the circumstances in which the new document was prepared may all become relevant.

2. Undue influence

A will may be challenged where another person overpowered the testator’s independent decision-making through coercion or improper influence.

Ordinary persuasion, family pressure, or involvement in the testator’s affairs does not automatically establish undue influence. The issue is whether the testator’s free will was effectively displaced.

Canadian courts distinguish undue influence from suspicious circumstances. Where undue influence is alleged, the burden of proving it generally remains on the person attacking the will.

3. Lack of knowledge and approval

A testator must know and approve the contents of the will.

This issue can arise where the document was prepared under unusual circumstances, contains unexpected provisions, substantially departs from prior estate plans, or was arranged by someone who benefits significantly from the change.

Where suspicious circumstances are established, the person seeking to uphold the will may be required to prove that the testator knew and approved its contents and possessed the necessary testamentary capacity.

4. Improper execution

Ontario’s Succession Law Reform Act sets formal requirements for the execution of wills. Subject to statutory exceptions, a will must be signed by the testator and properly witnessed.

However, a technical execution defect does not always end the analysis. Section 21.1 gives the Superior Court of Justice power, in qualifying cases, to declare a document valid if the court is satisfied that it sets out the deceased’s testamentary intentions even though it was not properly executed. That provision applies to qualifying deaths from January 1, 2022 onward.

5. Fraud or forgery

A will may also be attacked where there is evidence that a signature was forged, material facts were fraudulently misrepresented to the testator, documents were altered, or the purported will is not genuine.

These cases are highly evidence-dependent and may require handwriting evidence, document examination, financial records, witness testimony, or evidence concerning the circumstances in which the document appeared.

What are “suspicious circumstances”?

Suspicious circumstances are facts surrounding the preparation or execution of a will that raise legitimate concerns about capacity, knowledge and approval, or whether the testator’s free decision-making was compromised.

Examples may include:

• a major unexplained departure from prior wills;
• a vulnerable or dependent testator;
• a beneficiary playing a dominant role in arranging the new will;
• isolation of the testator from family members;
• unusual secrecy surrounding execution;
• substantial gifts to someone who participated in preparing or arranging the will.

Suspicious circumstances do not automatically invalidate a will. They affect how the evidence and burden of proof are assessed.

How is a will challenge started?

Ontario estate disputes are governed procedurally by Rule 75 of the Rules of Civil Procedure.

Where an application for a Certificate of Appointment of Estate Trustee is pending, a person with a financial interest may be able to file a Notice of Objection — Form 75.1. Ontario Court Services lists Form 75.1 specifically as the Notice of Objection used in contentious estate proceedings.

Depending on what has already occurred in the estate administration, the procedure may instead involve an application or motion for directions, a request for formal proof of the will, or other relief under Rule 75.

Timing matters. Once estate assets have been distributed, preservation and recovery issues can become more complicated. If there is a genuine concern about the validity of a will, obtaining advice early can help determine whether a procedural step is required to preserve the estate while the dispute is investigated.

For an overview of how litigation generally proceeds, see What is civil litigation in Ontario?.

What if the will is valid but I was unfairly excluded?

That may be a different legal issue.

An eligible dependant may potentially seek support from an estate even where the will itself is valid. Part V of Ontario’s Succession Law Reform Act allows the Superior Court of Justice to order adequate provision for the proper support of qualifying dependants where the deceased failed to make adequate provision.

A dependant-support claim is not the same as contesting the validity of the will. Different legal tests, evidence, procedures, and limitation rules apply.

This distinction is important because a person can have a potential estate claim even where there is no basis to invalidate the will itself.

How does ME Law assess a potential will challenge?

ME Law first identifies the actual legal issue rather than treating dissatisfaction with an inheritance as proof that the will is invalid.

The assessment may involve reviewing:

• the challenged will and earlier wills;
• the drafting lawyer’s file;
• medical and capacity evidence;
• communications involving the deceased and beneficiaries;
• financial and property records;
• the circumstances surrounding execution;
• evidence of dependency, influence, isolation, or unusual changes in the estate plan.

The objective is to determine whether there is evidence supporting a recognized challenge, what procedural steps may be required, whether estate assets need to be preserved, and whether litigation, negotiation, mediation, or another resolution strategy is appropriate.

If you are considering a challenge, What is a consultation at ME Law? explains how the initial legal assessment is structured.

Contact ME Law if you are concerned about the validity of a will or need advice about preserving your rights in an estate dispute.

In Ontario, a will may be challenged only on recognized legal grounds. The main grounds include lack of testamentary capacity, undue influence or coercion, improper execution, fraud or forgery, and certain ambiguities or errors affecting the validity or legal effect of the document. The question is not whether the will seems unfair, but whether there is a legally supportable defect.

Lack of testamentary capacity

A testator must have had the mental capacity required to make a valid will when it was executed. The court may consider whether the testator understood the nature and effect of making a will, the general extent of the property being disposed of, and the people who might reasonably be expected to benefit. Relevant evidence can include medical records, the drafting lawyer’s notes, witness evidence, earlier wills, and the testator’s conduct around the time of execution.

Undue influence or coercion

A will may be challenged where another person exercised influence so strong that the document no longer reflected the testator’s own free intentions. Mere persuasion, family involvement, or an opportunity to influence the testator is not enough on its own. The party alleging undue influence must prove it on the evidence. Courts may examine dependency, isolation, vulnerability, the beneficiary’s involvement in arranging the will, and unexplained changes that substantially benefit that person. Ontario courts apply these principles consistently with the Supreme Court of Canada’s framework in Vout v. Hay.

Improper execution

Ontario’s Succession Law Reform Act sets formal requirements for making and signing wills. Section 4 generally requires the testator’s signature and two attesting witnesses, subject to statutory exceptions. Failure to comply may create a validity issue. However, section 21.1 gives the Superior Court of Justice a curative power in qualifying cases to declare an improperly executed document valid if it sets out the deceased’s testamentary intentions. An execution defect therefore requires analysis rather than an automatic conclusion that the will is invalid.

Fraud or forgery

A will can also be attacked where there is evidence that the document or signature was forged, altered, fabricated, or procured through fraud. These allegations normally require evidence capable of supporting the particular claim, such as document or handwriting evidence, communications, witness testimony, or evidence about how the purported will was created and discovered.

Ambiguities or errors in the will

Ambiguity or drafting error does not automatically invalidate an entire will. Sometimes the issue is one of interpretation rather than validity, and the court may be asked to determine the proper meaning or legal effect of a provision. In other cases, an unusual provision may contribute to a broader challenge involving capacity, knowledge and approval, fraud, or suspicious circumstances. Its legal significance depends on the nature of the error and the surrounding evidence.

How ME Law assesses the grounds for challenge

The first step is to identify which legal ground, if any, is supported by the evidence. ME Law may review the challenged will, earlier wills, medical records, the drafting solicitor’s file, communications, witness evidence, and the circumstances surrounding execution. That analysis helps distinguish a genuine validity challenge from a disagreement over interpretation or dissatisfaction with the distribution of the estate.

For a broader explanation of litigation procedure, see What is civil litigation in Ontario?. Parties may also consider Dispute Resolution where an estate dispute can be addressed without a trial. What is a consultation at ME Law? explains how an initial legal assessment is structured.

Contact ME Law if you need advice about the validity of a will or the evidence required to support or defend a will challenge.

Testamentary capacity and undue influence frequently arise in Ontario will challenges because both concern whether a will genuinely reflects the deceased’s independent intentions. They are different legal issues, however: capacity concerns whether the testator had the mental ability to make the will, while undue influence concerns whether another person improperly displaced the testator’s free decision-making.

Testamentary capacity focuses on the testator’s ability to understand the will.

A capacity dispute may arise where the deceased was experiencing cognitive decline, serious illness, confusion, dementia, or other circumstances that raise questions about whether they understood the nature and effect of the will they were making.

The evidence may include medical records, the drafting solicitor’s file, witness evidence, previous wills, and information about the deceased’s condition and behaviour around the time the challenged will was executed. A diagnosis or advanced age does not automatically establish incapacity. The issue is the testator’s capacity at the legally relevant time.

Undue influence focuses on whether the will was made freely.

A person may have testamentary capacity but still be subjected to pressure, coercion, manipulation, or control by another person. ME Law’s existing estate-litigation material identifies evidence such as witness testimony, medical evidence showing vulnerability, financial records, sudden changes to a will, and patterns of isolation or dependency as potentially relevant in undue-influence disputes.

For a detailed discussion of this practice area, see Capacity & Undue Influence Litigation.

Why can the two issues appear in the same case?

Vulnerability may be relevant to both allegations. For example, cognitive decline may raise a capacity question while also making a testator more dependent on a caregiver, relative, or other person who participated in a significant change to the estate plan.

That overlap does not mean vulnerability proves either ground. The evidence must be assessed to determine whether the concern is lack of capacity, undue influence, both, or neither.

A substantial last-minute change, the exclusion of a previous beneficiary, increased dependency, or a beneficiary’s unusual involvement in arranging the new will may justify closer investigation, but the surrounding circumstances matter.

For the complete range of possible legal grounds, see What are the legal grounds for contesting a will in Ontario?.

How does ME Law assess these cases?

ME Law reviews the evidence surrounding the preparation and execution of the will rather than treating an unexpected inheritance result as proof of wrongdoing. This can include the challenged will, earlier wills, medical evidence, the drafting solicitor’s records, communications, financial information, and witness evidence.

If the evidence supports a formal estate dispute, Ontario contentious estate proceedings may engage Rule 75 of the Rules of Civil Procedure. Depending on the procedural stage, a Notice of Objection (Form 75.1) may also be relevant where an application for a Certificate of Appointment of Estate Trustee is pending. Ontario Court Services identifies Form 75.1 as the Notice of Objection used under Rule 75.

For the broader threshold question, see Can I contest a will in Ontario?

Contact ME Law if you are concerned that a will may have been affected by lack of testamentary capacity or undue influence.

Undue influence occurs when another person pressures, coerces, manipulates, or controls a testator to such a degree that the resulting will no longer reflects the testator’s own free intentions. It can arise through dependency, intimidation, isolation, or other forms of control, and it often occurs privately rather than in front of independent witnesses.

Ontario courts distinguish undue influence from ordinary persuasion or family influence. A relative, caregiver, or beneficiary may discuss estate planning with a testator or express a preference without necessarily exercising undue influence. The legal issue is whether the pressure became so significant that the testator’s independent decision-making was overborne.

Ontario authority following the Supreme Court of Canada decision in Vout v. Hay treats undue influence as something that must be established by the party challenging the will. Ontario courts have described the required influence as sufficiently overpowering that the document reflects the will of the influencing person rather than the voluntary intentions of the deceased.

How is undue influence different from lack of testamentary capacity?

The two concepts are related but legally distinct.

A person may have testamentary capacity — meaning they are mentally capable of making a will — but still be subjected to undue influence. Capacity asks whether the testator was capable of understanding and making the decision. Undue influence asks whether the decision was actually made freely.

This distinction is important because vulnerability does not automatically mean incapacity, and dependency does not automatically prove undue influence.

For a closer comparison of the two issues, see Why do testamentary capacity and undue influence commonly arise in Ontario will challenges?.

What circumstances can raise concerns about undue influence?

ME Law’s existing estate-litigation material identifies situations involving pressure, coercion or manipulation of a vulnerable individual and disputes concerning whether a will, trust, or property transfer was made freely and with full understanding.

Potential concerns can arise where, for example, a testator becomes highly dependent on another person, is increasingly isolated from family members, or makes a significant estate-planning change in circumstances where a beneficiary exercises substantial control.

Those circumstances may justify investigation, but they do not by themselves prove undue influence. The surrounding evidence and the effect of the alleged influence on the testator’s decisions remain critical.

For more on ME Law’s work in this area, see Capacity & Undue Influence Litigation.

What happens if undue influence affected the will?

If undue influence is established, the validity of the affected testamentary disposition may be challenged before the Ontario Superior Court of Justice. Contentious estate proceedings can engage Rule 75 of the Rules of Civil Procedure, depending on the relief sought and the stage of the estate administration.

The broader grounds on which a will may be challenged are explained in What are the legal grounds for contesting a will in Ontario?.

The next question in this FAQ series addresses the separate issue of how undue influence can actually be proved, including the types of evidence that may become relevant.

Contact ME Law if you are concerned that pressure, manipulation, dependency, or control may have affected a will or other estate-planning decision.

Proving undue influence in an Ontario will challenge can be difficult because the alleged pressure or manipulation often occurs privately. There may be no single document or witness that directly proves what happened. Instead, the case may depend on several pieces of evidence that, considered together, show whether another person improperly displaced the testator’s independent decision-making.

The person alleging undue influence generally must establish it through evidence. Suspicion alone — including an unexpected inheritance or an unusually favourable gift to one beneficiary — is not enough.

What evidence may help prove undue influence?

Witness testimony may provide evidence about the relationship between the testator and the person alleged to have exercised influence. Witnesses may be able to describe changes in the testator’s behaviour, increased dependency, isolation from other family members, or circumstances surrounding changes to the will.

Medical records may be relevant where they show that the testator was physically or cognitively vulnerable. Vulnerability does not itself prove undue influence, and a person may have testamentary capacity while still being susceptible to pressure. Medical evidence can nevertheless form an important part of the overall factual picture.

For the distinction between these two issues, see Why do testamentary capacity and undue influence commonly arise in Ontario will challenges?.

Financial records and sudden changes to the will may also be significant. A substantial change in the estate plan, particularly where it benefits someone who had considerable influence over the testator’s affairs, may justify closer examination. The change alone does not prove wrongdoing; the surrounding circumstances must be considered.

Patterns of isolation or dependency can also form part of the evidence. A testator who becomes increasingly dependent on one person for personal, financial, or practical support may be more vulnerable to influence. The relevant question remains whether that relationship crossed the line from assistance or persuasion into coercion or control.

For the legal meaning of the concept itself, see What is undue influence in an Ontario will challenge?.

Does one piece of evidence prove undue influence?

Usually not. Undue-influence cases are highly fact-specific. The court may have to assess the evidence as a whole rather than rely on a single circumstance.

The challenged will, earlier wills, witness testimony, medical records, and financial records may together help establish the context in which the testamentary decision was made. The objective is to determine whether the will represented the testator’s own intentions or whether another person’s pressure effectively overrode those intentions.

If a formal challenge proceeds, the dispute may come before the Ontario Superior Court of Justice through a contentious estate proceeding under Rule 75 of the Rules of Civil Procedure.

For the other recognized bases on which a will may be challenged, see What are the legal grounds for contesting a will in Ontario?.

How does ME Law assess evidence of undue influence?

ME Law examines the evidence in context rather than treating unusual circumstances as proof by themselves. The analysis may involve comparing the will with earlier testamentary arrangements and assessing witness testimony, medical evidence, financial records, sudden changes to the estate plan, and patterns of dependency or isolation.

The purpose is to determine whether there is a supportable basis for alleging undue influence and what litigation strategy is appropriate in the circumstances.

Contact ME Law if you are concerned that undue influence may have affected a will and need advice about the evidence required to challenge or defend it.

Strong evidence is required, which may include:

• The will and codicils

• Probate documents

• Estate accountings

• Medical records of the deceased

• Property and ownership records

• Executor correspondence

• Witness testimony

You can contest a will when there are legitimate concerns about its validity, fairness, or the conduct of those involved in its drafting or execution.

Success depends on the strength of your evidence, the grounds you rely on, and the court’s assessment of fairness and credibility.

Timelines vary depending on the type of claim. Generally, you have two years from when you knew or ought to have known about the issue. Some claims, such as dependant’s relief, must be filed within six months of probate

Typically, two years from the date you became aware of the issue. However, dependant’s relief claims must be filed within six months of probate being granted.

Most provinces, including Ontario, apply a two-year limitation period from the date of discovery.

Some claims have strict deadlines (e.g., six months after probate for dependant’s relief). It’s important to act early to avoid being time-barred

If you were financially dependent on the deceased and left without adequate support, you can apply to the court for relief. This requires filing the proper documents within six months of probate.

• The will and codicils

• Probate documents

• Estate financial records

• Property titles and ownership records

• Medical and capacity assessments

• Trust agreements

• Communications with the executor

If the executor is hiding information, delaying the process, or mismanaging assets, you can apply to court for directions, compel disclosure, or even seek their removal.

An executor who ignores the will or mismanages assets may be in breach of fiduciary duty. Courts can order compliance or appoint a replacement.

If probate is not initiated, the estate cannot be legally administered. In that case, beneficiaries or interested parties may apply to the court to appoint a new estate trustee.

This is a serious breach of fiduciary duty. The court can remove the executor, compel repayment, and in some cases, pursue criminal consequences.

Yes. Courts may remove executors who mismanage the estate, delay distribution, act dishonestly, or fail to follow their duties.

Yes. Interested parties can apply to the court to replace an executor if there is evidence of misconduct or inability to act.

Executors cannot be casually replaced, but courts can intervene where there is cause, such as misconduct, incapacity, or refusal to act.

Yes, in certain cases. If the estate property must be sold or distributed, beneficiaries may be required to vacate—even if they lived there before the death.

It begins with document review and attempts at negotiation or mediation. If unresolved, it may progress to formal court applications, hearings, or trial.

Costs vary depending on complexity, but we provide clear estimates and discuss cost-saving options. Some matters may allow costs to be paid from the estate.