- Ontario's basic limitation period is two years — you generally must start your claim within two years, or it can be barred.
- The two years usually runs from when you discovered (or reasonably should have discovered) the claim, not necessarily from the date of the event.
- There is also a 15-year ultimate limitation period that applies regardless of discovery.
- A debtor's written acknowledgment of a debt, or a partial payment, can reset the two-year clock.
- The clock can be suspended for minors and incapable persons, and some claims (like certain real-property claims) have different periods.
- Missing the deadline usually means your claim is gone — so if time is tight, act now and get advice.
The Short Answer
In Ontario, you generally have two years to start a lawsuit. That two-year “basic limitation period” usually runs from the day you discovered the claim — not always the date of the event itself. There is also a 15-year ultimate deadline that applies no matter what. Miss the applicable period and your claim can be permanently barred, no matter how strong it is. If your deadline may be close, the safe move is to act immediately.
The Two-Year Basic Rule
Ontario's Limitations Act, 2002 sets a general rule: a claim must be started within two years. This applies to most everyday disputes — unpaid debts, breach of contract, property damage, and the kinds of claims that end up in Small Claims Court. Importantly, the two-year period is the same whether you sue in Small Claims Court or the Superior Court; choosing the smaller court does not buy you extra time.
When the Clock Starts: Discoverability
The single most misunderstood part of limitation law is when the clock starts. It is not automatically the date of the event. Under the discoverability rule, the two years generally begins on the day you first knew, or reasonably ought to have known, all of the following:
- That some loss or damage had occurred
- That it was caused by the act or omission of the person you would sue
- That a legal proceeding would be an appropriate way to seek a remedy
For a hidden defect or a loss you could not reasonably have known about right away, the clock may start later than the underlying event. But do not rely on this — courts assess what you reasonably ought to have known, and assuming a late start date is risky.
The 15-Year Ultimate Deadline
Sitting behind the two-year rule is an ultimate limitation period of 15 years. This acts as a hard backstop: regardless of when a claim is discovered, a proceeding generally cannot be brought more than 15 years after the act or omission that caused it, subject to limited exceptions. In practice, the two-year rule is what matters in the vast majority of cases, but the 15-year cap can be decisive in cases involving long-delayed discovery.
How a Debt Can Reset the Clock
For claims to recover a debt, there is an important rule that can work in a creditor's favour. If, before the limitation period expires, the debtor acknowledges the debt in writing or makes a partial payment, the two-year clock can start over from the date of that acknowledgment or payment.
You are owed money and the two-year period is approaching. The debtor emails, “I know I owe you the $6,000 — I'll pay you when I can,” or sends a $500 partial payment. That written acknowledgment or partial payment can reset the clock, giving a fresh two-year window from the date it was made. Keeping such messages and records can be valuable.
Exceptions & Different Periods
The two-year rule is the default, but not universal. Some claims follow different timelines:
| Situation | How It Differs |
|---|---|
| Minors & incapable persons | The clock is generally suspended until the person is no longer a minor or incapable, or has a litigation guardian |
| Certain real-property claims | Some claims involving land fall under different legislation with a longer period |
| Claims with notice requirements | Some defendants require a short written notice within a set time before suing |
| Acknowledged debts | A written acknowledgment or partial payment can reset the two-year period |
Some claims require you to give written notice within a very short window — sometimes measured in days — before you can even sue. These short notice rules are easy to miss and can defeat an otherwise valid claim, so check them early.
Why the Deadline Is So Strict
Limitation periods exist to provide certainty and finality: evidence fades, memories dim, and people are entitled to move on rather than face stale claims indefinitely. Because of that purpose, an expired limitation period is a complete defence — the other side can raise it to defeat your claim entirely, and the court will generally give effect to it regardless of the merits. That is what makes missing the deadline so damaging.
Tricky Timing Situations
A few recurring scenarios cause confusion about exactly when the clock runs, and they are worth understanding:
- Instalment debts. Where money is owed in instalments, each missed payment can, depending on the agreement, carry its own limitation period running from when that payment was missed. That can mean some instalments are still claimable even if the earliest ones are out of time.
- Ongoing or repeated harm. Where wrongful conduct continues over time — such as a recurring nuisance — the timing analysis can be more complex than a single-event claim, and fresh conduct may give rise to fresh claims.
- Claims between defendants. If you are sued and want to bring in another party who should share responsibility, a claim for contribution or indemnity generally has its own two-year period that runs from when you were served, not from the original event.
- Adding a claim later. Trying to add a new claim or a new defendant after starting a case does not escape the limitation rules — the new claim generally must still be within its own period.
These situations show why a blanket “two years from the event” assumption can be misleading. The safest approach is to identify the earliest plausible start date for each distinct claim and treat that as your deadline, rather than hoping a more generous interpretation will apply.
How It Works in Practice
The practical lesson is to treat two years as a firm outer limit and to act well before it. If you are still trying to resolve things informally, remember that negotiating does not pause the clock — a demand letter, as covered in our guide on demand letters before suing, is useful but does not extend your time. If a resolution is not close and the deadline is nearing, the safe course is to start the claim to preserve your rights, following the process in our guide on how to sue in Small Claims Court.
A useful habit is to calendar your limitation deadline the moment a dispute arises, working backward from the earliest date you could be said to have known about the claim, and to build in a comfortable buffer rather than aiming for the last possible day. Filing a claim does not force you to fight it out immediately — you can still negotiate or settle after it is issued — but it stops the clock and protects your position. In other words, if you are unsure whether you are in time, the cost of filing early is small compared with the cost of discovering, too late, that your right to sue has already expired.
What to Do If Time Is Running Out
- Identify your likely start date — when you first knew of the loss and its cause.
- Do not rely on a late discovery date unless you are confident it applies.
- Do not let negotiations run out the clock — the limitation period does not pause for settlement talks.
- Get advice immediately if the deadline is close, and start the claim to preserve your rights if needed.
Common Mistakes
- Assuming the clock starts later than it does
- Letting settlement discussions delay filing past the deadline
- Overlooking a short notice requirement for a particular defendant
- Not keeping written acknowledgments or partial payments that could reset a debt clock
- Waiting until the last week to seek advice
Common Myths
Myth: “I have plenty of time — it just happened a year ago.”
Risky. With a two-year period, a year is already halfway gone, and the exact start date can be earlier than you think. Act sooner rather than later.
Myth: “Sending a demand letter protects my deadline.”
False. Only starting the claim in time protects your rights. Demand letters and negotiations do not pause the clock.
Myth: “Small Claims Court gives me more time to sue.”
False. The same two-year basic limitation period applies in Small Claims Court as in the higher court.
Worried your time to sue may be running out? Call our Toronto Small Claims team at 416-274-2222 for a free, confidential consultation before your deadline passes.
Frequently Asked Questions
In most cases, two years. Ontario's Limitations Act sets a basic limitation period of two years, which generally runs from the day you discovered (or reasonably should have discovered) the claim. There is also a 15-year ultimate limitation period that applies regardless of discovery.
Usually on the day you knew, or reasonably ought to have known, that you had a claim — that a loss occurred, that it was caused by the person you would sue, and that a legal proceeding was an appropriate remedy. This "discoverability" rule means the start date is not always the date of the underlying event.
It is a hard backstop. Even if a claim is not discovered until much later, the ultimate limitation period generally bars proceedings started more than 15 years after the act or omission that gave rise to the claim, subject to limited exceptions.
For debt claims, yes, in certain circumstances. If the debtor acknowledges the debt in writing, or makes a partial payment, before the limitation period expires, the two-year clock can start over from the date of that acknowledgment or payment. This is a specific rule for claims to recover a debt.
Generally, your claim is barred — meaning the other side can rely on the expired limitation period as a complete defence, regardless of how strong your case is on the merits. That is why missing the deadline is one of the most serious mistakes in litigation.
Yes. The same two-year basic limitation period applies whether your claim is in Small Claims Court or the Superior Court of Justice. Choosing Small Claims Court does not give you extra time.
Yes. Certain claims have their own rules — for example, some claims involving real property fall under different legislation with a longer period, and some claims against particular defendants carry short notice requirements. Because these vary, it is important to check the specific type of claim.
The limitation clock is generally suspended while a potential plaintiff is a minor or is legally incapable and without a litigation guardian. The period typically begins to run once that circumstance ends, though the details depend on the situation.
No. Sending a demand letter, negotiating, or waiting for a response does not pause the limitation period. Only starting the claim within the deadline protects your rights, so you should not let settlement talks run out your time.
If there is any chance your deadline is approaching, yes — urgently. Limitation questions can be technical, particularly around when the clock started and whether any exception applies. Getting advice early can be the difference between a live claim and a lost one.