Can a Grandchild Claim Against a Grandparent's Estate in Ontario?

Being close to a grandparent — even being raised by one — does not, on its own, give a grandchild a legal right to inherit in Ontario. A grandchild's claim against a grandparent's estate is possible, but only in a narrow set of circumstances, and the path depends heavily on whether the grandparent left a will and what your relationship with them actually looked like.

If you believe you were unfairly left out of a grandparent's estate, it helps to understand exactly which door — if any — is open to you before you spend time and money pursuing a claim the law doesn't support.

Grandchildren Have No Automatic Right to Inherit

Ontario law does not treat grandchildren the way it treats a spouse or a child. A grandparent is free to leave their estate to whomever they choose, including skipping grandchildren entirely, and that choice is not, by itself, something a court will overturn just because it feels unfair.

If a grandparent dies without a will, Ontario's intestacy rules under the Succession Law Reform Act (SLRA) generally direct the estate to a surviving spouse and children first. A grandchild typically only comes into the picture if their own parent — the grandparent's child — died before the grandparent did, in which case that grandchild may stand in their deceased parent's place and receive the share their parent would have received. Simply being a grandchild of someone who died without a will does not create an entitlement if your parent is still alive.

If There Is a Will That Leaves You Out

A will that leaves out a grandchild is not automatically challengeable. Ontario courts will only interfere with a validly made will on specific legal grounds, including:

• Lack of testamentary capacity at the time the will was made
• Lack of knowledge and approval of the will's contents
• Undue influence over the testator
• Fraud
• Failure to meet the formal signing and witnessing requirements

Disagreeing with how a grandparent chose to divide their estate is not, on its own, one of these grounds. A successful challenge requires evidence connected to one of the categories above, not simply a belief that the outcome was unfair.

The One Path That Doesn't Depend on the Will: Dependant's Support

Part V of the SLRA creates a separate route that isn't about challenging the will itself. It allows certain people the deceased was actually supporting, or was legally obligated to support, immediately before death to apply for support from the estate — regardless of what the will says or what the intestacy rules would otherwise provide.

This provision is not limited to spouses and children. In the right circumstances, a grandchild who was genuinely dependent on a grandparent — for example, one who was being raised or financially supported by that grandparent — may be able to bring a claim under this Part. This is a fact-specific test, and simply having a warm relationship with a grandparent is not the same as being a dependant in the legal sense.

Claims like this are subject to a firm deadline: generally six months from the date an estate certificate is granted, though a court has some discretion to allow a later claim against any part of the estate not yet distributed. Waiting to see how things unfold before getting advice is a common and costly mistake in this area.

Questions to Ask Before You Pursue a Claim

• [ ] Did your grandparent leave a will, and does it mention you at all?
• [ ] If there is no will, is your own parent (the grandparent's child) still living?
• [ ] Were you financially dependent on your grandparent, or did they have an ongoing legal obligation to support you?
• [ ] Has a Certificate of Appointment of Estate Trustee already been granted, and if so, when?
• [ ] Do you have documents or witnesses who can speak to your relationship and any support that was provided?

Working through these questions honestly, ideally with a lawyer, will tell you quickly whether you have a realistic claim or whether the estate's distribution, however disappointing, is simply how the law works.

Frequently asked questions