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Wills & Estates

What Is Estate Litigation in Ontario and How Does an Estate Lawsuit Work?

TSL Written by the Treadstone Law Team· Updated November 6, 2026

Estate litigation is a court dispute about a deceased person's estate, such as whether a will is valid, how an estate trustee is handling the estate, or who is entitled to what. In Toronto, the Estates List of the Superior Court of Justice hears estate, trust and capacity matters, including Rule 74 and 75 proceedings and guardianship proceedings.

Most disputes follow a recognizable path. Before the court will require a will to be formally proved, a person challenging it must point to some evidence that, if accepted, would call its validity into question. The court then has considerable discretion and flexibility to set a process for resolving the contest. Certain estate lawsuits are referred to mandatory mediation unless the court grants an exemption. Deadlines can be short, such as six months after probate for a dependant support claim, though a late claim may be allowed against any undistributed part of the estate, and two years from discovery for most other claims.

How long a case takes depends on how complicated the issues are, how many people are involved and whether it settles, so no honest single timeline exists. A lawyer can help you understand the steps and deadlines that apply to your situation.

Key takeaways

  • In the Toronto Region, the Estates List of the Superior Court of Justice hears estate, trust and capacity matters.
  • Before the court will require a will to be formally proved, a person challenging it must point to some evidence that, if accepted, would call its validity into question.
  • Certain estate lawsuits are referred to mandatory mediation unless the court grants an exemption.
  • Deadlines vary by type of claim, so confirm which one applies to you as early as you can.
This is general information, not legal advice. It doesn’t create a lawyer–client relationship, and the rules can change. For advice on your situation, a Treadstone wills & estates lawyer can help.

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Sources

Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.

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