Estate litigation in Ontario sits at the crossroads of family law, trust law, and civil procedure. It is an area where legal principles, human emotion, and financial realities collide—often explosively. For both counsel and mediators, a strong grasp of the broad estate litigation framework is essential to navigating these cases effectively and reaching durable resolutions.

Most estate disputes fall into several recurring categories.

Will challenges are perhaps the most high-profile, often arising from allegations of lack of testamentary capacity, undue influence, improper execution, or even fraud. These cases frequently turn on the strength of the proof addressing “suspicious circumstances”—as framed in Vout v. Hay, 1995 CanLII 105 (SCC)^[1]—with a robust drafting-solicitor file and contemporaneous medical evidence commonly carrying the day.

Dependent support claims are another common flashpoint, brought under Part V of the Succession Law Reform Act^[2], with “adequate support” assessed in light of both need and the deceased’s moral obligations, per Cummings v. Cummings, 2004 CanLII 9339 (ON CA)^[3].

Executor and trustee disputes are also frequent, particularly in cases alleging breach of fiduciary duty, misuse of estate assets, or the need for removal due to conflict or incapacity. The decision in Radford v. Wilkins^[4] remains a touchstone, articulating the principles that justify removal, including the necessity of protecting the estate’s administration from dysfunction^[5].

Passing of accounts proceedings, in which the court reviews the executor’s actions, can become contentious when beneficiaries object to disbursements, investments, or perceived inequities. In Burton v. Assaf^[6], decades of bitter litigation over an estate’s administration ultimately led the Court of Appeal to uphold strict judicial intervention and declare one of the parties a vexatious litigant, demonstrating how these disputes can spiral far beyond the original accounting issues. In other cases, such as Zimmerman v. McMichael Estate^[7], the court’s meticulous review of the fiduciary’s accounts led to the denial of compensation and orders to repay unsubstantiated withdrawals, underscoring the high evidentiary burden on trustees and attorneys to justify every transaction.

Trust and property rights, rather than estate administration, are at the heart of some disputes. This is common in blended family situations or where assets were held jointly. In Pecore v. Pecore^[8], the Supreme Court of Canada clarified the presumption of resulting trust in parent–adult child joint accounts, a principle that still drives many Ontario estate disputes today.

The procedural framework defined by Ontario’s Rules of Civil Procedure^[9] and the Estates Act^[10]is where all of these conflicts operate. A Notice of Objection under Rule 75.03^[11] is often the first formal step in a will challenge, halting probate until the dispute is resolved. Many matters begin as applications, which rely on affidavit evidence, but may be converted into actions when live testimony is needed. In Toronto, Ottawa, and Windsor (County of Essex), contested estates, trusts and substitute-decision matters are subject to mandatory mediation under Rule 75.1 of the Rules of Civil Procedure^[12], and Ontario’s Civil Rules Review^[13] has proposed expanding mandatory mediation more broadly.

Limitation periods must be navigated carefully. In Ontario, the two-year clock runs from the day a claim is “discovered” under s. 5 of the Limitations Act, 2002^[14]—that is, when the plaintiff knew or ought reasonably to have known the material facts and that a proceeding was appropriate. The Supreme Court in Grant Thornton LLP v. New Brunswick^[15] confirmed that discovery requires more than suspicion but less than certainty. It is enough that the known facts support a plausible inference of liability, judged objectively in light of the plaintiff’s circumstances^[16].

In Leibel v. Leibel^[17][17], the Superior Court treated a will challenge as a “claim” under the Limitations Act, 2002, applying the basic two-year period that presumptively runs from the date of death (s. 5(2)), subject to discoverability on the facts.

More recently, in Shannon v. Hrabovsky^[18], the Court of Appeal confirmed that the two-year clock in a will challenge need not start until the challenger has enough facts to form a plausible inference of liability—often when they can actually review the will—rather than on mere knowledge of the death or rumours of disinheritance.

Applied to solicitor-negligence in a “no-contest clause” misadvice scenario, the two-year period typically starts against the first lawyer when the beneficiary knew or ought to have known that counsel’s advice or filing triggered the clause and caused loss^[19](forfeiture risk, adverse cost exposure, or settlement leverage erosion), and a separate two-year period against the successor lawyer begins only when the client knew or ought to have known that the second retainer failed to correct or reasonably mitigate that harm—not merely on the date counsel changed^[20].

Beyond the general two-year, discovery-based clock in the Limitations Act, 2002, actions that survive a death and are brought by or against an estate for “wrongs to the person or property” face a hard two-year limit running from the date of death under s. 38(3) of the Trustee Act^[21]—a period not subject to discoverability, as confirmed by the Court of Appeal in Waschkowski v. Hopkinson Estate[22], and reaffirmed in Giroux Estate v. Trillium Health Centre<^[23]. Where both regimes appear to apply, the Court of Appeal has held that s. 38(3) prevails because it’s scheduled under s. 19 of the Limitations Act, 2002 (Levesque v. Crampton Estate^[24]). The doctrine of fraudulent concealment can still toll s. 38(3) in the right case—see Giroux Estate and its recent application in Beaudoin Estate v. Campbellford Memorial Hospital^[25].

The human element is often the real driver in estate litigation, rather than legal. Grief, sibling rivalries, long-standing resentments, and shifting alliances can shape a case as much as the strength of any legal argument. These forces can entrench positions, escalate minor disputes, and resist compromise even when a settlement would clearly serve the parties’ interests. Personal history often drives these cases as much as doctrine: see Banton v. Banton^[26] (predatory-marriage and family conflict colouring the entire will dispute.

Mediation can prove uniquely valuable in estates litigation. Unlike the public, adversarial courtroom process, mediation offers a confidential and flexible setting in which both the legal and personal dimensions of a dispute can be addressed. Mediation can preserve family relationships where possible, facilitate creative settlements—such as staggered payments, property transfers, or shared use of sentimental items—that courts may never order, and avoid the years of delay and expense that trial can bring. These benefits are especially pronounced in high-conflict situations, where unresolved tensions could otherwise fester for a generation.

For practitioners, success in this field demands technical precision and human insight. Counsel must be fluent in the rules, statutory provisions, and evidentiary burdens that govern estate disputes, while also preparing for mediation with the same thoroughness as for trial. Mediators must provide a space where legal rights are balanced against the potential for emotional reconciliation, guiding parties toward solutions that address both needs.

Ontario’s estate litigation landscape is broad, complex, and deeply human. As the province moves toward expanded mandatory mediation, the ability to navigate both the legal and emotional terrain with confidence will be an increasingly valuable skill, one that can lead to fair settlements and to lasting peace among families facing one of life’s most difficult transitions.