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Undue Influence and Wills in Ontario

Suspect a caregiver or relative pressured someone into a will or gift? Learn the Ontario test, who carries the burden and what evidence matters.

Wills & Estates4 min readTSLBy the Treadstone Law Team · OntarioUpdated October 28, 2026
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Key takeaways
  • If undue influence is alleged against a will, the burden is on the party attacking the will.
  • For gifts and transfers made during life, a presumption of undue influence can arise where the relationship carries potential for domination.
  • Suspicious circumstances evidence can shift the legal burden on capacity and knowledge back to the party defending the will.
  • Strong evidence usually comes from documents, medical records and independent witnesses rather than suspicion alone.

When an older relative changes a will or transfers property late in life, and a caregiver or one family member benefited, it is natural to wonder whether pressure was involved. Undue influence is a legal allegation that pressure affected someone's decisions, and whether it applies depends on the facts.

The law treats wills and lifetime gifts differently. This article explains the difference, who carries the burden, and the kinds of evidence that matter, so you know what you would need to show.

Wills and gifts are treated differently

If undue influence is alleged against a will, the burden is on the party attacking the will. That means that if you suspect pressure, you are the one who must prove it.

For gifts and transfers made while the person was alive, the approach is different. A presumption of undue influence arises where the relationship between the giver and the receiver carries potential for domination. The receiver must then show the gift resulted from the giver's full, free and informed thought.

SituationWho carries the burden on undue influence
Challenge to a willThe party attacking the will
Lifetime gift or transfer in a relationship with potential for dominationThe receiver, once the presumption arises

Related grounds that often travel with undue influence

Undue influence claims are often paired with questions about capacity and knowledge. The party defending a will must prove due execution, knowledge and approval of the contents, and testamentary capacity.

A challenger can meet an evidential burden with evidence of suspicious circumstances that, if accepted, would tend to negative knowledge and approval or capacity. The legal burden then reverts to the party defending the will. Where suspicious circumstances raise doubt about capacity, that party must prove capacity on a balance of probabilities.

The capacity test asks whether the person understood the nature and effect of a will, the property being disposed of and the claims to be given effect to, with no disorder of the mind poisoning affections and no insane delusion influencing the disposition.

Evidence that tends to matter

Courts decide on evidence, so what you can document is more useful than what you believe. Examples of what people try to gather:

Gifts, joint accounts and powers of attorney

A gratuitous transfer from a parent to an adult child is presumed to be held on resulting trust for the parent. The child bears the burden of rebutting it, on a balance of probabilities, by showing the parent's actual intention at the time of transfer. This presumption has been applied to bank accounts put into joint names with adult children, and the court weighs all the evidence of intention, including the terms of any power of attorney granted to the receiver.

An attorney for property owes fiduciary duties, including the core duty to act exclusively for the grantor's benefit. Where the attorney is also the estate trustee, beneficiaries have been allowed to seek leave to obtain an accounting for the period before death. How this applies to you depends on your situation, so it is worth confirming with a lawyer.

If someone is still alive and you worry about serious harm to their finances, the Public Guardian and Trustee must investigate allegations that a person is incapable of managing property and that serious harm is occurring or may occur. The helpline is 1-800-366-0335.

What to do next

Frequently asked questions

Is persuasion the same as undue influence?

Not necessarily, and where the line falls depends on the facts. If undue influence is alleged against a will, the burden of proving it is on the party attacking the will.

Does a caregiver receiving a gift mean undue influence?

Not automatically. For a gift made during life, a presumption can arise where the relationship carries potential for domination, and the receiver must then show the gift came from the giver's full, free and informed thought. Whether that applies depends on the facts.

Do I need to prove lack of capacity too?

Not necessarily. Capacity is a separate question. If suspicious circumstances raise doubt, the party defending the will must prove capacity on a balance of probabilities.

Can I claim for care I gave a parent?

Possibly. A child who provided years of personal care on a promise of a share of property has succeeded in unjust enrichment, and the claimant must prove enrichment, corresponding deprivation and absence of juristic reason. Results turn heavily on the facts.

Sources

Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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