September 16, 2025

How to Contest a Will in Ontario: Grounds, Process, and Time Limits

Thinking of contesting a will in Ontario? Learn who can challenge a will, the legal grounds, how the process starts, who must prove what, and the time limits.

Losing someone is hard enough. Discovering that their will does not seem right - or that it changed suddenly near the end - can leave you feeling powerless and unsure where to turn.

Ontario law does give family members a way to question a will they honestly believe is wrong. Challenging a will is a serious step, and it is not right for every situation. But understanding how the process works can help you decide whether to look into it, and how quickly you need to move.

What Does It Mean to Contest a Will?

To contest a will (also called challenging a will) means asking the court to decide that the will is not valid, in whole or in part. If the challenge succeeds, the court may set the will aside. An earlier, valid will might then apply instead. If there is no earlier will, the estate is shared out under Ontario's rules for when someone dies without a will. Those rules are called intestacy, and they follow a fixed family-tree order.

Who Is Allowed to Challenge a Will?

Not just anyone can step forward. You need what lawyers call standing - a close enough connection to the estate that the court will listen to you. Think of standing as your ticket into the courtroom. In Ontario, the people who usually have standing are:

• Beneficiaries - people named to inherit in the current will, or in an earlier version of the will
• Intestacy heirs - close relatives who would inherit under Ontario's no-will rules if the will were set aside, such as a spouse or children
• Dependants - people the deceased was supporting, or had a legal duty to support, right before death

If you do not fit one of these categories, the court is unlikely to hear your challenge, no matter how strongly you feel. An estate lawyer can tell you quickly whether you have standing.

The Grounds for Contesting a Will

You cannot challenge a will simply because you are hurt or surprised by it. You need a legal reason, called a ground. Ontario recognises five main grounds:

• Lack of testamentary capacity - testamentary capacity is the mental ability to make a will. The person must understand that they are making a will, know roughly what they own, and remember who they might be expected to provide for. Illness, dementia, or heavy medication can rob someone of this capacity.
• Undue influence - this means someone coerced the will-maker: real pressure that overpowered their free choice. It is more than nagging or normal family influence. It is pressure so strong that the will reflects the influencer's wishes, not the will-maker's.
• Lack of knowledge and approval - the will-maker must actually know and approve what the will says. If they signed without understanding the contents, because they could not read it or it was misrepresented to them, the will may fail.
• Improper execution - a will must be signed and witnessed correctly. In Ontario this generally means the will-maker signs, and two witnesses are present together to witness it. There are narrow exceptions, but a will signed the wrong way can be invalid.
• Fraud or forgery - the will, or a signature on it, was faked, or the will-maker was deliberately tricked into signing.

Sometimes more than one ground applies. For example, a frail, isolated parent might have lacked capacity and been unduly influenced at the same time.

How a Will Challenge Begins

Before an executor can fully deal with an estate, they often apply to the Ontario Superior Court of Justice - the province's probate court - for a Certificate of Appointment of Estate Trustee. This certificate is the official document that confirms the executor's authority to act. (An executor, called an estate trustee in Ontario, is the person who carries out the will.)

If you want to pause that certificate while your concerns are investigated, you can file a Notice of Objection with the court - sometimes called a caveat. It acts like a stop sign: it tells the court not to issue the certificate until your objection is looked at. Filing one early can prevent assets from being handed out before the questions are answered.

Gathering the Evidence

A will challenge stands or falls on evidence. Suspicion alone is not enough - you need facts. The most useful evidence often includes:

• Medical records - doctor's notes, hospital charts, and assessments that show the will-maker's mental state around the time the will was signed
• The drafting lawyer's file - the notes of the lawyer who prepared the will can reveal how alert the will-maker was and whether anyone else was in the room
• Witnesses - family, friends, neighbours, or caregivers who can describe the will-maker's condition and who was involved
• The will and earlier wills - comparing versions can show sudden, unexplained changes that benefit one person

You do not have to gather all of this yourself. A lawyer can obtain records and take statements, and the court process has formal tools for getting documents from the people who hold them.

Who Has to Prove What?

In law, the burden of proof decides which side has to convince the court. To begin, the person defending the will (lawyers call them the propounder) must show it was properly signed and witnessed. If the will looks regular on its face, the law generally presumes the will-maker had capacity, and the burden shifts to you to point to a problem - for example, undue influence or fraud, which the person challenging generally must prove.

But there is an important exception. If suspicious circumstances surround the will, the burden can shift back the other way. Suspicious circumstances are red flags around how the will came to be. Examples include:

• A caregiver or new friend who arranged the will and also benefits from it
• An elderly, isolated, or dependent will-maker cut off from other family
• Sudden, last-minute changes that favour one person

When suspicious circumstances exist, the person defending the will must prove the will-maker truly had capacity and knew and approved the contents. This can make a real difference to your chances, which is why an experienced lawyer looks closely at how the will was made.

Counting the Cost - Money and Feelings

Challenging a will is not free, and it is not quick. It helps to know what you are taking on before you start.

There is an old belief that the estate always pays everyone's legal bills. That is no longer reliable. Modern courts often apply the normal civil rule that the losing side may have to pay some of the winner's costs, unless the dispute was genuinely caused by the will-maker's own actions or the challenge was reasonably necessary. Lose a challenge, and you could end up paying not only your own lawyer but part of the other side's too.

There is an emotional cost as well. These disputes are between people who are often grieving, and they can strain family bonds for years. That does not mean you should stay silent when something is truly wrong - only that it is worth weighing carefully, and getting honest advice about your prospects first.

Why Time Is Not on Your Side

If you have doubts, act promptly. There are two reasons. First, a Notice of Objection is most useful before the certificate is issued and assets are distributed - once money has been paid out, it is far harder to unwind. Second, legal claims are subject to limitation periods, which are strict time limits that can bar a claim completely if you wait too long. The exact limits depend on the type of claim, so do not guess.

The safest move is simple: if something feels wrong, talk to an estate lawyer promptly. Getting advice early keeps your options open.

Key Takeaways

• Only certain people can challenge a will: beneficiaries, intestacy heirs, and dependants
• You need a legal ground, such as lack of capacity, undue influence, lack of knowledge and approval, improper execution, or fraud
• File a Notice of Objection early to pause the Certificate of Appointment while concerns are investigated
• Evidence is everything - medical records, the drafting lawyer's notes, and witnesses matter most
• Suspicious circumstances can shift the burden onto the people defending the will
• Challenges carry real financial and emotional risk, and strict time limits apply, so get advice quickly