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Part 6 – Testamentary Capacity and Undue Influence: Safeguarding the Integrity of Your Will

In our previous blogs, we delved into various aspects of estate planning in Ontario, shedding light on important considerations, including the constraints imposed on testamentary freedom by legislations like the Ontario Family Law Act and Succession Law Reform Act. Testamentary freedom forms the cornerstone of estate planning, allowing individuals to distribute their assets as they wish upon their passing. However, at the heart of testamentary freedom lies the prerequisite that the person creating the will possesses testamentary capacity. In this blog, we will explore the crucial elements of testamentary capacity and the potential for undue influence, providing insights into how these factors can impact the integrity of your will.

Testamentary Capacity

Testamentary capacity is a foundational requirement for the validity of a will. It signifies the legal and mental capacity of an individual to understand the nature and consequences of creating a will. In Ontario, testamentary capacity is assessed based on specific criteria, including:

  1. Understanding: The will maker must grasp the nature and extent of their assets, along with identifying potential beneficiaries, including anyone who may have a legal or moral claim to the inheritance.
  2. Appreciating Consequences: It is crucial that the individual comprehends the implications of their decisions and how these choices will influence the distribution of their assets.
  3. Freedom from Disorders: Testamentary capacity necessitates freedom from mental disorders or conditions that could influence the terms of the will.
  4. Voluntariness: The act of creating the will must be a voluntary one, devoid of any undue influence or coercion.

It’s important to note that testamentary capacity is a legal capacity test, and while medical conditions may affect an individual’s testamentary capacity, they are not the sole determinants. For example, an individual diagnosed with late-stage dementia may still possess testamentary capacity, while someone without dementia may lack it due to other reasons.

Undue Influence

Undue influence refers to the exertion of pressure or persuasion on the will maker that exceeds normal persuasion. It can involve manipulating the individual into making decisions against their true wishes or better judgment. Undue influence is a significant concern because it compromises the testamentary capacity of the will maker, potentially resulting in a will that does not reflect their genuine wishes.

Potential for Litigation

As discussed in our blog “The Risks of Jointly Holding Property in Your Estate Plan,” estate litigation revolving around resulting trusts has become increasingly prevalent. One of the other most common forms of estate litigation centers on claims that the will maker lacked testamentary capacity.

Having a challenge brought against your will on the grounds of testamentary capacity can lead to unnecessary delays in estate administration and substantial reductions in estate assets. If a court determines that a will maker lacked testamentary capacity, the will is considered void. If the will maker had a previous will, that will takes effect; otherwise, they are deemed to have died intestate.

Historically, there were incentives to challenge wills based on a lack of testamentary capacity, even without sufficient evidence This was due to the presumption that the estate would cover all parties’ legal costs. However, recent court amendments have shifted this presumption, allowing the successful party to typically recover their costs. This shift in presumption of costs has created an additional incentive to only bring such claims when sufficient evidence supports them.

The Role of Lawyers

Estate lawyers play a pivotal role in ensuring their clients possess the necessary testamentary capacity when creating a will. Their responsibilities extend beyond drafting the legal document; they must also assess their client’s mental capacity. During interactions with clients, experienced lawyers meticulously document the individual’s mental state, lucidity, and understanding of the decisions being made. These notes serve as a crucial resource in case the will is contested on the grounds of testamentary capacity.

If a will is challenged, these notes provide valuable insights into the will maker’s mental state at the time of drafting and executing, helping establish their capacity to comprehend the consequences of their decisions and confirming the absence of undue influence. This documentation can be a potent tool in upholding the validity of the will and ensuring the testator’s true wishes are honored. While retaining a lawyer will not prevent claims being brought that challenge the validity of your will, your lawyers’ notes may dissuade such claims from being pursued, and if they are, may allow your estate to recover costly legal expenses. 


Testamentary capacity and the potential for undue influence are integral considerations in estate planning. Ensuring that the will maker possesses the mental capacity to make informed decisions and is not subject to undue pressure is essential for creating a valid and legally binding will. Estate lawyers play a crucial role in safeguarding the integrity of the will by assessing their clients’ capacity and meticulously documenting their interactions. This ensures that, in case of a will challenge, there is a robust record to support the testator’s capacity and the authenticity of their wishes. It underscores the importance of seeking professional legal guidance when planning your estate, safeguarding your legacy, and the interests of your beneficiaries.