This is general information, not legal advice, and reflects Ontario law as of September 26, 2026.
The basic rule: two years from the day you discovered your claim
Ontario's Limitations Act, 2002 (S.O. 2002, c. 24, Sched. B) sets the general deadline for most civil claims — breach of contract, negligence, property damage, and most personal injury claims among them. Under section 4, you generally cannot start a court proceeding more than two years after the day your claim was "discovered."
Discovery isn't always the day something went wrong. Under section 5(1)(a), a claim is discovered on the earlier of the day you actually knew, or the day a reasonable person in your situation ought to have known, all of the following:
- That the injury, loss, or damage had happened.
- That it was caused by an act or omission — something someone did, or failed to do.
- That a specific person — the one you'd be suing — was responsible for it.
- That a court proceeding would be an appropriate way to seek a remedy, given the nature of the harm.
Once you know — or reasonably should know — all four, the two-year clock starts running, even if that's weeks or months after the underlying incident. Section 5(2) presumes you knew on the day the act or omission happened unless you can show otherwise, so "I didn't realize" is a case you have to make, not an assumption the law makes for you.
The 15-year outside limit — even if you found out late
Discoverability can push your two-year clock later than the date of the incident itself. To stop that from running indefinitely, section 15 of the Act sets an ultimate limitation period of 15 years, counted from the day the act or omission actually happened — not from when you found out about it, and not subject to discoverability at all.
In practice, that means two deadlines run at once: the two-year clock from discovery, and a hard 15-year backstop from the underlying event. Whichever one arrives first generally closes the door on your claim.
When the clock pauses: minors and incapacity
The Act builds in a small number of pauses:
- Minors. Under section 6, the basic two-year period doesn't run while the person with the claim is under 18 and has no litigation guardian representing them.
- Incapacity. Under section 7, the same kind of pause applies while someone is incapable of starting a proceeding because of a physical, mental, or psychological condition, and has no litigation guardian.
- The 15-year ultimate period has its own, narrower version of these pauses under section 15(4) — including where a defendant willfully conceals the claim or misleads the claimant about pursuing it.
These pauses are the exception, not the rule. They don't apply just because someone was young or unwell at some point in their life — only while the specific claim itself was affected.
Not every claim runs on this clock
The Limitations Act, 2002 is the general rule, not the only rule. Claims against a municipality or other government body, some insurance and accident-benefit claims, and a handful of other claim types are governed by their own separate statutes — often with shorter notice periods that run alongside, not instead of, the Act's deadlines. If your situation involves a government body, an insurer, or a workplace injury, confirm which specific notice period applies before you assume you have the full two years.
Not sure exactly which date applies to you?
Working out your own discovery date, and checking it against both the two-year and 15-year clocks, is exactly the kind of date math that's easy to get wrong under stress. Our free Ontario Deadline Calculator runs both calculations for you, cites the exact section of the Act behind every result, and flags any date it can't determine on its own rather than guessing.
Frequently asked questions
Does the 2-year clock start on the day I was hurt, or the day I found out? Generally the day you discovered the claim — which the Limitations Act, 2002 defines as when you knew, or reasonably should have known, that you were harmed, who caused it, and that a lawsuit would be an appropriate response. That's often the same day as the incident, but not always.
What happens if I miss the limitation period? A court can dismiss your claim outright, regardless of how strong it is on the merits. Missing the deadline is generally fatal to the claim, not just a procedural inconvenience.
Is the deadline different in Small Claims Court than in Superior Court? No. The Limitations Act, 2002's basic and ultimate periods apply the same way no matter which court hears the claim. What differs between courts is the dollar-value limit and the procedure — not the deadline itself.