Limitation Periods in Ontario: How Long Do You Have to Sue?

A limitation period is a hard deadline. Miss it and it does not matter how strong your case is, how clearly the other side was in the wrong, or how much money you lost — the claim is statute-barred and the court will not hear it. Limitation periods are the single most common way a good case is lost before it starts.

The short answer: In Ontario, the basic limitation period under the Limitations Act, 2002 is two years from the day the claim was discovered — not necessarily the day the loss happened. There is also a 15-year ultimate limitation period running from the act or omission itself. Important exceptions apply to minors, incapable persons, sexual assault claims, demand obligations, and claims about land, and some claims — especially against municipalities — carry written notice deadlines measured in days.

#What is the basic limitation period in Ontario?

Under the Limitations Act, 2002, the basic limitation period is two years. It applies broadly — breach of contract, negligence, professional negligence, property damage, unpaid debts, most personal injury claims — unless a different statute says otherwise.

The critical detail is what the two years runs from. It is not automatically the date of the accident, the breach, or the bad advice. It runs from the day the claim was discovered.

#What does "discoverability" actually mean?

Discoverability is the concept that a limitation clock should not run against someone who could not reasonably have known they had a claim. Under the Act, a claim is discovered on the day the person first knew, or ought reasonably to have known, all of the following:

1. That the injury, loss, or damage had occurred;
2. That it was caused by or contributed to by an act or omission;
3. That the act or omission was that of the person you want to sue; and
4. That a court proceeding would be an appropriate means to seek a remedy.

The Act also contains an important presumption: a person is presumed to have known all of this on the day the act or omission took place, unless they prove otherwise. In other words, the default assumption works against you, and it is the claimant who has to displace it.

This matters most in cases where harm is hidden. A structural defect that only shows up years after construction, an accounting error nobody notices until an audit, a professional's mistake that only surfaces when a deal collapses — in each case the two years may start when the problem reasonably came to light, not when the mistake was made. But do not treat discoverability as a safety net. Courts scrutinise what a reasonable person in your position ought to have known, and "I didn't get around to investigating" is not an answer.

The fourth element — whether a proceeding was an "appropriate means" — can also postpone the clock, for example where the parties were engaged in a genuine remedial process. It is fact-specific and unreliable to plan around.

#What is the 15-year ultimate limitation period?

Because discoverability can push a deadline far into the future, the Act imposes a backstop. The ultimate limitation period bars a claim 15 years after the day the act or omission on which the claim is based took place — whether or not the claim has been discovered.

So there are two clocks running at once, and the earlier one to expire wins:

The ultimate period is itself subject to exceptions — it does not run, for example, during periods when a claimant is a minor or incapable, and it does not apply to the categories the Act says have no limitation period at all.

#Which claims have no limitation period?

The Act lists a limited set of claims where no limitation period applies. The most significant are:

• Sexual assault claims. There is no limitation period for a proceeding based on a sexual assault. The Act also removes the limitation period for certain other assault claims — including where the assault occurred in an intimate relationship or a relationship of dependency — recognising that survivors often come forward many years later.
• Proceedings to enforce a court order, or an order enforceable in the same way as a court order.
• Proceedings for a declaration where no consequential relief is sought.
• Certain support arrears under family legislation and certain claims by the Crown, for example to recover fines or penalties.

If your claim falls in one of these categories, delay does not extinguish your right to sue. Evidence still degrades with time, though, so early advice is still the better course.

#How do minors and incapable persons change the clock?

The Act stops the clock in two significant situations:

• Minors. A limitation period does not run while the person with the claim is under 18, unless a litigation guardian has been appointed to act for them. In practice this often means a minor's claim is not time-barred until two years after their 18th birthday — but the appointment of a litigation guardian can start the clock earlier, so the analysis is fact-specific.
• Incapable persons. The clock does not run while a person is incapable of commencing a proceeding because of their physical, mental, or psychological condition, and again is not represented by a litigation guardian.

These provisions are protective, not automatic. Whether someone was legally "incapable" during a period is frequently contested.

#What about demand obligations — loans repayable on demand?

Money lent "on demand" used to create real uncertainty: did the two years run from the day the money was advanced?

The Act settles it. For a demand obligation, the claim is discovered on the first day there is a failure to perform the obligation after a demand for performance is made. Practically, that means the clock on a demand loan starts when you make the demand and the borrower fails to pay — not when the loan was advanced.

This is an important tool for lenders and family members who have made informal loans, but it depends entirely on the obligation genuinely being a demand obligation on its terms. If your loan document sets a fixed repayment date, the ordinary rules apply from that date.

#Claims about land: the Real Property Limitations Act

Not everything falls under the Limitations Act, 2002. Claims to recover land, and various mortgage-related claims, are governed instead by the older Real Property Limitations Act, which generally uses a 10-year period rather than two.

That statute is where you find the rules behind adverse possession, boundary disputes, and the time limits on enforcing money secured by a mortgage. The interaction between the two statutes is genuinely technical — whether a particular claim is "about land" or is really a contract or negligence claim can be litigated on its own. If your dispute touches real property, do not assume either the two-year or the ten-year rule without advice. (See our guides on power of sale vs. foreclosure in Ontario and how to stop a power of sale.)

#The deadlines that catch people out: notice requirements

This is where most claims are quietly lost, because a notice deadline is not a limitation period — it is a separate, far shorter requirement that must be satisfied before you sue.

The best-known example is a claim against a municipality for personal injury caused by the non-repair of a road or sidewalk — the classic slip-and-fall on an icy sidewalk or trip on a broken curb. Under Ontario's Municipal Act, 2001, you must give the municipality written notice of the claim, including the date, time, and location of the injury, within 10 days of the incident.

Two things save some claimants: the legislation provides that failure to give notice is not a bar where there is a reasonable excuse and the municipality is not prejudiced by the delay, and the notice requirement does not apply in cases of death. But relying on either is a gamble you should never take deliberately. Ten days is ten days. If you fall on municipal property, send written notice immediately and get advice the same week.

Other short deadlines to be aware of:

• Claims against the Crown in right of Ontario require advance written notice before a proceeding is commenced.
• Occupiers' liability claims for snow and ice on private property carry their own short written notice requirement.
• Insurance claims — particularly statutory accident benefits after a motor vehicle collision — carry tight notice and application deadlines measured in days, entirely separate from any limitation period.
• Defamation in a newspaper or broadcast carries both a very short notice period and a shortened limitation period under the Libel and Slander Act.
• Employment, human rights, and construction-lien claims all have their own statutory time limits that are shorter than two years or run on different triggers.

The exact figures vary by statute and are amended from time to time. The reliable rule is simply this: if a government body, an insurer, a construction project, or a media outlet is involved, assume there is a short deadline and check it immediately.

#Can a limitation period be changed by agreement?

Sometimes. The Act allows parties to a business agreement to vary or exclude limitation periods by agreement, subject to conditions — one reason commercial contracts often contain a clause shortening or extending the time to bring a claim.

Parties can also sign a tolling agreement, in which they agree to suspend the running of a limitation period while they try to negotiate. If you are in settlement discussions as a deadline approaches, a tolling agreement — or simply issuing the claim to protect the deadline and then continuing to negotiate — is the professional answer. Never let a deadline pass because talks "seemed to be going well."

Note that negotiating, on its own, does not stop the clock. Neither does a demand letter, an insurer's acknowledgment, or an ongoing internal complaint process. Only issuing a claim reliably stops it.

#Why acting early matters more than the deadline suggests

Even where you have time, waiting costs you:

• Evidence disappears. Documents get deleted under retention policies, phones are replaced, site conditions change.
• Memories fade, and witnesses move, retire, or die.
• Leverage falls. A claim advanced promptly reads as serious; one raised at the eleventh hour invites the argument that you never really believed in it.
• Identifying the right defendant takes time. Adding a party after a limitation period has expired is difficult, and getting the corporate defendant's name wrong can be fatal.

Treat the two-year period as an outer boundary, not a plan.

#How Tokas Lex can help

Limitation analysis is one of the first things a litigator does on any new file, and it is worth doing properly. We can identify which statute and which clock applies to your claim, whether discoverability helps you, whether a notice deadline has already been triggered, and what needs to be issued or served immediately to protect your position.

If you think you may have a claim — or you have been told one is coming — contact Tokas Lex or learn more about our civil litigation services. If the amount at stake is $35,000 or less, our guide to Small Claims Court in Ontario explains the process.

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This article provides general information about Ontario law and is not legal advice. Limitation periods and notice requirements are highly fact-specific and change from time to time. If a deadline may be running, consult a lawyer promptly.