Contesting a Will for Undue Influence in Ontario: What You Must Show

You think the will does not reflect what your relative really wanted. Perhaps a caregiver became very close near the end, or one family member controlled access and decisions, and the will changed in their favour. You want to know what a court would need to see.

This article sets out how the burden of proof works in Ontario will disputes, what undue influence requires you to prove, and how to start gathering evidence. Disputes turn heavily on facts, and time limits and costs matter, so speak with a lawyer early.

Who has to prove what

Someone propounding a will, meaning the person asking the court to uphold it, has the legal burden of proving due execution, knowledge and approval of the contents, and testamentary capacity. Once due execution is shown, a rebuttable presumption places an evidential burden on those challenging the will.

This split is why it matters to identify which ground you are really relying on. Undue influence is different from the other grounds because the burden of proving it sits with you.

Suspicious circumstances

A challenger can meet the evidential burden by pointing to suspicious circumstances, meaning evidence that tends to negate knowledge and approval or testamentary capacity. If they do, the legal burden reverts to the propounder of the will.

Note what that does and does not cover. Suspicious circumstances are tied to knowledge and approval, and to capacity. They do not automatically prove undue influence, which you must establish yourself. A claim often runs on more than one ground at once, and the evidence for one may support another.

Undue influence: what you must show

If undue influence is alleged against a will, the burden of proving it is on those attacking the will. In plain terms, you must show that the will does not reflect the will-maker's own wishes because someone else's pressure overrode them. This article does not set out the detailed elements courts look for, since that depends on the facts and a lawyer can explain how it applies to yours.

Being close to the will-maker, helping with their care, or even being named in the will is not by itself proof of pressure. What matters is the evidence about what actually happened.

• Who arranged the meeting with the lawyer, and who was present.
• Who gave the instructions and who paid.
• Changes from earlier wills, and whether the reasons make sense.
• Isolation of the will-maker from other family or friends.
• Dependence on one person for care, money or daily decisions.
• Statements the will-maker made at the time about their wishes.

Capacity is a separate question

Many will challenges raise capacity alongside undue influence. Ontario's mental capacity guidance says a person is incapable of a decision if they cannot understand the information relevant to it or the consequences of making or not making it, and that capacity is decision-specific and can change over time. That is the test for managing property and granting a power of attorney. It is not the test for making a will.

So medical records or a finding about a power of attorney do not answer the will question by themselves. They may still be useful evidence, but the law treats these as separate decisions.

What to do next

• Obtain a copy of the will and any earlier wills you can find.
• Write down what you saw and heard, with dates, while memories are fresh.
• Identify witnesses: friends, neighbours, health workers, the drafting lawyer.
• Note what medical or care records might exist, without trying to take them yourself.
• Do not confront the person who benefits or remove anything from the home.
• See an estates litigation lawyer promptly to confirm deadlines, standing and the strength of your evidence.

Litigation can be expensive and stressful for a family. A lawyer can help you weigh the evidence you have against the cost and, where it makes sense, explore resolution before a trial.

Frequently asked questions