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№ 22 Wills & Estates

Test for Mental Capacity to Make a Will in British Columbia

See how British Columbia courts decide whether a will-maker was mentally capable: the age rule, case law test, burden of proof and timing.

Wills & Estates4 min readTSLBy the Treadstone Law Team · British ColumbiaUpdated November 1, 2026
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Key takeaways
  • WESA requires a will-maker to be 16 or older and mentally capable, and the detailed test comes from case law.
  • Suspicious circumstances relating to capacity put the burden of proving capacity on the person propounding the will.
  • Capacity disputes are decided on an application to prove the will in solemn form.

If you doubt that someone could make a will, you probably want a checklist of the questions a court will ask. The honest answer is that the law sets a framework, and the outcome turns on evidence about the particular person.

This article walks through the framework used in British Columbia: the statute, the case law, who has to prove what, and the practical steps and timing points to be aware of.

This article covers the law of British Columbia.

Step one: the statutory requirements

Section 36(1) of the Wills, Estates and Succession Act says a person who is 16 or older and mentally capable of doing so may make a will. A will made by a person under 16 is not valid.

The Act does not define "mentally capable". That test is supplied by case law, which BC courts apply with section 36. The leading authority is Banks v Goodfellow (1870), whose wording has stayed the same while later cases refined its criteria.

Step two: the questions the courts ask

The case law test is a set of questions about the will-maker's mind. One of them deals with delusions: the Supreme Court of Canada applied the test to insane delusions affecting a will-maker's gifts in Ouderkirk v. Ouderkirk. The full list of questions and their current wording is best confirmed with a lawyer who can review the judgments.

Capacity is judged on the evidence in each case. Different kinds of evidence may matter, such as witness accounts and records from around the time the will was made, but how a court weighs them depends on the facts.

Step three: who has to prove what

The burden of proof is often the deciding issue. Capacity is presumed, and suspicious circumstances can rebut that presumption. Where the suspicious circumstances relate to mental capacity, the person propounding the will reassumes the legal burden of establishing capacity.

IssueWho generally carries the burden
Capacity, once suspicious circumstances relating to capacity are shownThe person propounding the will
Fraud or undue influence, in generalThe person alleging it
Undue influence, after the challenger shows potential dependence or dominationThe party defending the will, under WESA s. 52

Suspicious circumstances do not raise the standard of proof, which stays at the balance of probabilities, but the evidence is scrutinized in line with the gravity of the suspicion. The s. 52 reversal applies only once the challenger has shown a position of potential dependence or domination; without that, the ordinary rule applies.

Step four: where and when it is decided

A person who receives notice of a probate application can oppose a grant by filing a notice of dispute (Form P29) under Rule 25-10. A formal challenge is made by applying for an order proving the will in solemn form under Rule 25-15.

What to do next

If you believe a will-maker lacked capacity, concentrate on preserving evidence and getting timing advice early. If you cannot show incapacity or undue influence but you are a disinherited spouse or child, the court may order provision out of the estate where a will does not make adequate provision for proper maintenance and support.

Frequently asked questions

Is there a medical test that decides capacity?

The law treats capacity as a legal question decided by the court on the evidence. The statute does not define the test, which comes from case law. A lawyer can explain how medical evidence may fit into your case.

What if the will-maker was 15 when they signed?

A will made by a person under 16 is not valid. A person who is 16 or older must also be mentally capable.

Is lack of capacity the same as undue influence?

No. Capacity concerns the will-maker's mental ability. Undue influence concerns pressure from someone in a position of potential dependence or domination, and WESA section 52 can shift the onus once that position is shown.

How long do I have to challenge a will?

It depends on the type of claim. The Limitation Act sets a basic 2-year period from discovery, but it may not govern every validity challenge, and a wills variation claim has a 180-day limit from the grant. Get advice early to confirm which deadline applies.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. British Columbia 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 lawyer who practises in British Columbia. Reach us at 1-844-900-1070 or send our Team a message.

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