How long you have to sue — and why a missed deadline can quietly end a valid claim.
Who this is for: Anyone in Ontario wondering "Is it too late to take this to court?" — over a debt, a contract, a botched job, an injury, or a property problem. What you'll get: the five things to understand about limitation periods, examples by claim type, the special situations that change the math, and a quick-reference table.
⚖️ This is a general guide, not legal advice. It can't account for your specific situation. Use it to get oriented, then confirm the details with a licensed Ontario lawyer.
Why this matters more than people think
A limitation period is the legal deadline to start a lawsuit. Here's the hard part: it's usually fatal. If you sue after the period expires, the other side can have your case dismissed no matter how strong it is — the merits never get heard. People lose perfectly good claims this way, not because they were wrong, but because they waited.
That's why the single most useful thing this guide can tell you is: if you might have a claim, find out your deadline early — not when you finally get around to it.
The 5 things to understand
1. The basic rule: two years from "discoverability"
Ontario's main statute on this is the Limitations Act, 2002. Its general rule is a basic limitation period of two years, running not necessarily from when the bad thing happened, but from when you discovered (or reasonably should have discovered) the claim. As of writing the basic period is two years — but because exceptions and special statutes exist, verify how it applies to your specific claim.
Tip: "Two years from discovery" is the headline. Almost every nuance below is about when discovery happened or which exception applies.
2. What "discoverability" actually means
The clock generally starts on the day you first knew — or a reasonable person in your shoes ought to have known — all of the following:
- That an injury, loss, or damage occurred;
- That it was caused by someone's act or omission;
- That that person was responsible; and
- That a court proceeding would be an appropriate way to remedy it.
This is why two people harmed on the same day can have different deadlines — one discovered the problem immediately, the other only later. Discoverability is fact-specific, which is both its flexibility and its danger.
⚠️ Watch out: Don't gamble on a late discovery date to buy yourself time. Courts look at when you reasonably should have known, not just when you actually did. Assuming the latest possible start date is risky.
3. The 15-year backstop (the ultimate limitation)
Even if you genuinely didn't discover a claim for years, the Limitations Act, 2002 sets an ultimate limitation period — an outer wall. As of writing this is generally fifteen years from the day the act or omission took place, regardless of discovery. After that, the claim is normally gone for good. Verify the current ultimate period, as exceptions apply.
Think of it as two locks on the door: the basic period (≈2 years from discovery) usually closes first, but the ultimate period (≈15 years from the event) closes the door for everyone eventually.
4. Special situations change the math
Several situations pause, extend, shorten, or replace the ordinary rules:
- Minors and people under incapacity. The clock generally does not run while a claimant is a minor or is incapable of bringing a claim (and isn't represented by a litigation guardian). It can start later — but confirm the specifics, which are detailed and fact-driven.
- Short government / municipal notice periods. Claims against municipalities and public bodies can carry their own, much shorter notice requirements — sometimes you must give written notice within a very brief window (e.g., for a slip-and-fall on a sidewalk) or lose the right entirely. These run separately from the two-year period. Always check for a short-notice rule when a public body is involved — and verify the current period.
- The Construction Act has its own timelines. Construction lien deadlines are set by the Construction Act, not the Limitations Act, 2002, and they are short and strict. Don't apply the two-year rule to a lien.
- Other statutes can set their own clocks. Certain claims (some against specific defendants or under specific statutes) have unique periods. When in doubt, assume your claim might have a special rule.
5. You can sometimes agree to change the deadline
Parties can enter a limitation (tolling) agreement — a written agreement to suspend or extend the limitation period, often to allow settlement talks to continue without forcing a rushed lawsuit. Section 22 of the Limitations Act, 2002 permits a limitation period to be suspended or extended by agreement; the Act sets no writing requirement, but never rely on an oral one.
Tip: If the other side asks you to "hold off suing while we negotiate," don't just trust a handshake. Get a written tolling agreement, or file your claim to protect yourself. A friendly delay can quietly run out your clock.
Quick-reference table
These are general illustrations under the Limitations Act, 2002. Specific facts and other statutes can change them — verify your deadline with a lawyer.
| Type of claim | General starting point | Typical period (as of writing — verify) |
|---|---|---|
| Breach of contract | When you discovered the breach/loss | ~2 years from discovery |
| Unpaid debt | Often the date payment was due / last acknowledged | ~2 years from discovery (acknowledgment can reset it) |
| Negligence (e.g., personal injury) | When you discovered the injury, cause, and responsible party | ~2 years from discovery |
| Property damage | When you discovered the damage and its cause | ~2 years from discovery |
| Claim against a municipality / public body | Event date — plus a short notice requirement | Short notice window + ~2 years (verify both) |
| Construction lien | Set by the Construction Act, not this Act | Short, strict — verify |
| Minor / incapable claimant | Clock generally paused | Starts later — confirm |
| Ultimate backstop (most claims) | Date of the act/omission | ~15 years regardless of discovery |
⚠️ The "debt" trap: A debtor who acknowledges a debt or makes a partial payment can restart the clock. That can help a creditor — but a single ambiguous email shouldn't be relied on either way. Get advice before you assume a debt is alive or dead.
A short example
Scenario: A homeowner notices basement leaks two years and one month after a renovation. They assume they've missed the boat and do nothing. In fact, the discoverability rule may mean their clock started when they reasonably discovered the defect — not the day the work finished. Whether they're in time depends on the facts. The mistake would be giving up without checking. The opposite mistake — assuming you have years when a short municipal notice or a construction timeline applies — is just as costly.
Mini-FAQ
Is the deadline really two years? The basic period is generally two years from discovery — but exceptions, special statutes, short notice rules, and the ultimate 15-year limit all exist. Treat "two years" as a starting point, not a guarantee.
What if I'm not sure when I "discovered" my claim? That's exactly the kind of question a lawyer assesses. Discoverability is fact-specific and is often where cases are won or lost.
Can I still sue if a little time has passed? Maybe. The only safe answer is to get advice quickly, because every day that passes narrows your options — and some claims (liens, municipal notices) have very short windows.
What's the safest thing I can do right now? Write down the key dates, gather your documents, and speak to a lawyer early. Protecting a deadline is far easier than reviving a dead claim.
How Treadstone Law can help
Limitation periods are unforgiving, but they're also assessable — and the earlier you ask, the more options you keep. Treadstone Law is a digital-first Ontario firm that helps people across the province figure out whether they're still in time and act before a deadline closes.
- Flat-fee assessments and litigation services, so you know the cost up front.
- Online intake — get your situation in front of us in minutes.
- All-Ontario virtual service, office in Mississauga.
Not sure if it's too late? Don't guess — find out. Call 1-844-900-1070, visit treadstonelaw.ca/litigation, see treadstonelaw.ca/pricing, or treadstonelaw.ca/start-file today.
This is not legal advice
This guide 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.