Naming a Guardian for Minor Children in Your Ontario Will

For most parents, the most important sentence in their will is not the one about money. It is the one that says who will raise their children if both parents are gone.

Naming a guardian for minor children in your Ontario will is one of the most consequential decisions in estate planning — and one of the most commonly deferred. Parents often tell themselves they will get to it when they have more time, or when the children are older. The problem is that the need for a guardian arises suddenly and without warning. If you have children under 18 and no will, Ontario's courts decide who raises them. That decision may not go the way you would have chosen.

This article explains how guardianship of children works in Ontario, the legal effect of naming a guardian in your will, and what to consider when making this choice.

What Is a Guardian of the Person?

In Ontario, a guardian of the person is an individual authorized to make decisions about a child's care, upbringing, education, and health — decisions that a parent would normally make. This is distinct from a guardian of property (someone who manages a child's financial assets, such as an inheritance).

The legal framework for guardianship of children in Ontario is primarily found in the Children's Law Reform Act and the Substitute Decisions Act. Courts overseeing guardianship applications are guided by the paramount principle of the best interests of the child.

How Naming a Guardian in a Will Works

Under Ontario law, a parent who has custody of a child may name a guardian for that child in their will. This is sometimes called a testamentary appointment of a guardian.

The 90-Day Temporary Period

A testamentary appointment does not permanently grant guardianship — it creates a temporary authority lasting 90 days from the date the testator (the parent who made the will) dies. During those 90 days, the named guardian may care for the child under the authority of the will.

To become the child's guardian permanently, the named person must apply to the court for a formal order. The court will consider the best interests of the child and may grant or modify the appointment, or appoint someone else entirely if the evidence warrants.

This structure is important to understand: naming someone in your will is a strong signal to the court of your wishes, but it is not a guarantee that person will be appointed. What it does provide is a smooth transition — a clear, immediate authority in the days following death while the formal court process is initiated.

What if There is a Surviving Parent?

Guardianship questions typically only arise when both parents are unable to care for the child. If one parent is alive and has been involved in the child's life, they generally continue as the child's primary caregiver regardless of what any will says. A will's guardian appointment comes into practical effect when there is no surviving parent able to act.

Where parents are separated or divorced, the surviving parent typically assumes sole responsibility for the children even if they were not the primary custodial parent before. A guardian named in one parent's will would not normally override the surviving parent's rights.

Choosing the Right Guardian

This is a deeply personal decision, and there is rarely a perfect choice. Here are the key factors most parents weigh:

Shared Values

The person you choose should share your core values around education, religion, culture, family, and how children should be raised. This matters more than proximity or wealth.

Relationship With the Children

A guardian who already knows and loves your children will provide more continuity and stability than someone who is a more distant figure in the children's lives, even if that more distant person might seem more "suitable" on paper.

Practical Capacity

Guardianship is a long-term, demanding commitment. Consider the person's age, health, existing family commitments, and whether they have the time and energy to take on additional children. A 70-year-old grandparent might be a loving choice but may struggle with the physical demands of raising a toddler for 15 years.

Willingness

Before naming anyone as guardian, have the conversation. A person who is surprised and unwilling is unlikely to be an effective guardian. Knowing your wishes allows your nominee to prepare — practically and emotionally — for the possibility.

Geographic Considerations

If the named guardian lives in another city or country, the children may need to change schools, leave their community, and lose other support structures. This is not necessarily disqualifying but should be thought through.

Financial Situation

A guardian does not need to be wealthy — your estate plan (life insurance, registered accounts, testamentary trusts) can provide the financial resources to support the children. The guardian's role is caregiving, not funding. A well-drafted will separates the financial management function (a trustee) from the personal care function (a guardian), so the guardian is not burdened with managing money.

Naming Backup Guardians

What if your first choice cannot act — because they have died, have become incapacitated, or simply cannot take on the responsibility when the time comes? Your will should name one or more backup guardians in order of preference. This is not an expression of doubt in your primary choice; it is practical planning that ensures there is always a designated person for the court to consider.

The Guardian and the Trustee: Separate Roles

Many parents instinctively want to name the same person as both guardian and trustee of the children's inheritance. This is understandable — it feels simpler. But separating the roles has real advantages:

• A trustee managing money can provide a check on the guardian's spending
• The person best suited to raise children may not be the best financial manager
• Separating the roles reduces the risk that the guardian makes financial decisions based on their own interests rather than the children's

The guardian and trustee can still cooperate — the trustee pays amounts from the trust to support the children's care, coordinating with the guardian's needs. The separation simply adds a layer of oversight.

Updating the Guardianship Appointment

The person you name today may not be the right choice in ten years. Life changes: relationships drift, health declines, family situations shift. Review your guardianship appointment whenever you review your will — at minimum every five years and after any major life event. The appointment is only as useful as its current accuracy.

What Happens if There is No Will?

If both parents die without a valid will, no testamentary guardian appointment exists. Any person wishing to be appointed guardian of the children must apply to the court. There may be competing applications — different family members may want custody. The court will ultimately decide in the best interests of the children, but the process may be prolonged and contested, during which the children's care situation is uncertain.

A will with a clear guardian appointment does not guarantee a particular outcome, but it provides the court with your evidence of who you trusted and why, and gives the named guardian a legal basis to care for the children immediately while the court application is prepared.

Frequently asked questions