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How Long Can a Trust Last in Ontario? Perpetuity Rules Explained

Can a trust run forever? Ontario law says no. Here's how duration limits work, and why they're different from the federal 21-year trust tax rule.

Wills & Estates5 min readTSLBy the Treadstone Law team · OntarioUpdated 2026-07
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Key takeaways
  • A long-standing legal principle across Canadian common law, often called the rule against perpetuities, reflects a policy concern that's been part of trust law for a very long time:…
  • Ontario has provincial legislation addressing how long certain trusts and future interests can remain unresolved before they must vest in a beneficiary.
  • It's easy to confuse this with the federal 21-year deemed disposition rule, which is a separate, tax-focused concept: most trusts are treated, for income tax purposes, as though they…

A trust can feel like a permanent solution: property held indefinitely, managed by a trustee, for beneficiaries who may not even be born yet. But Ontario law doesn't actually allow property to be tied up in a trust forever. There are limits, and they need to be built into the trust document itself.

If you're planning a trust meant to benefit more than one generation, or you're just wondering what happens once a trust's purpose is fulfilled, this is the piece that matters.

The Basic Idea: Property Can't Be Tied Up Forever

A long-standing legal principle across Canadian common law, often called the rule against perpetuities, reflects a policy concern that's been part of trust law for a very long time: property shouldn't be locked away from free use and ownership indefinitely, controlled by the wishes of someone long dead, with no point at which it's meant to vest outright in someone. A trust that doesn't specify when it will actually end, or when a beneficiary's interest becomes theirs outright, runs into this principle.

How Ontario Approaches This Today

Ontario has provincial legislation addressing how long certain trusts and future interests can remain unresolved before they must vest in a beneficiary. The specific rules, including how the applicable time period is calculated and which kinds of trusts are affected, are technical and depend heavily on how the trust is drafted. This isn't something to calculate yourself: a lawyer drafting your trust document builds in provisions designed to comply with current Ontario law, rather than leaving the trust's validity to chance.

This Is Different From the Federal "21-Year Rule" for Trust Taxation

It's easy to confuse this with the federal 21-year deemed disposition rule, which is a separate, tax-focused concept: most trusts are treated, for income tax purposes, as though they disposed of their capital property on a recurring anniversary roughly every 21 years, whether or not anything was actually sold. That rule is about tax timing, not about how long a trust is legally allowed to exist. A trust can be well within Ontario's duration rules and still face a 21-year tax event, and vice versa — the two questions need to be considered separately, ideally with both a lawyer and an accountant involved.

Trusts That Are Built to Last Longer

Some trusts are deliberately designed around an event rather than a fixed calendar date. A charitable trust may continue as long as it serves its charitable purpose, a spousal or life-interest trust typically lasts for the life of the spouse, and a disability planning trust may be designed to continue for the beneficiary's lifetime. Each of these comes with its own drafting considerations for how, and eventually whether, the trust winds up.

Trusts That Are Built to End Sooner

Other trusts are designed to be short-lived by intention. A trust created to hold a minor's inheritance only until they reach an age chosen by the person who set it up, for example, ends automatically and pays out once that age is reached. These are among the more straightforward trusts to draft precisely because the end point is simple to define.

What Happens When a Trust's Time Is Up

Once a trust reaches its end point, whether that's a fixed event, an age, a death, or a legal duration limit, the trustee must distribute what remains according to the trust's terms. A trust document that doesn't clearly address what happens at the end is one of the more common sources of dispute among beneficiaries, precisely because there's no obvious default answer once that gap is discovered.

Questions Worth Asking Your Lawyer

Frequently asked questions

Can a trust in Ontario last forever?

Generally, no. Ontario law limits how long a trust's terms can remain unresolved before property must vest in a beneficiary, though the specific rules are technical enough that they need to be built into the drafting, not assumed.

Is the rule against perpetuities the same thing as the 21-year tax rule?

No. They're separate concepts that happen to share similar subject matter. One limits how long a trust can legally exist without vesting; the other is a federal income tax timing rule that applies to most trusts regardless of their legal duration.

Do charitable trusts have to end at some point?

Charitable trusts are often treated differently than trusts for individual beneficiaries under Ontario's duration rules, but the specific exceptions and how they apply depend on the structure. This is worth confirming directly with your lawyer rather than assuming.

What happens if my trust deed doesn't say when it ends?

It can create real uncertainty, and potentially a dispute among beneficiaries or even a court application to interpret what was intended. Addressing the end point clearly when the trust is drafted is far simpler than resolving it after the fact.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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