Ontario Limitation Periods · Limitations Act, 2002
Ontario's Limitations Act, 2002 governs when court proceedings must be commenced. Missing a limitation period is one of the most common causes of malpractice claims for Ontario lawyers. This guide covers the key limitation periods, including the free interactive calculator below.
Enter the incident date and case type. Instantly calculate all applicable limitation periods — 2-year basic, 15-year ultimate, minors' tolling, municipal notice, construction lien, and defamation — with citations, days remaining, and urgency warnings. No login required.
Open Calculator (Free) →Reference guide for Ontario litigators. Last updated 2026.
The general rule. A claim must be commenced within 2 years from the date the claim was discovered (i.e., the plaintiff knew or reasonably ought to have known of the injury, cause, identity of defendant, and that a proceeding would be appropriate). The discovery rule under s. 5 governs when the clock starts.
An absolute backstop. No claim can be commenced more than 15 years after the date of the act or omission, regardless of when it was discovered. Does not apply to claims based on sexual assault, sexual exploitation of a minor, or certain proceedings involving minors.
If the plaintiff was a minor when the claim was discovered, the 2-year basic limitation period does not begin until the plaintiff turns 18. A minor who discovers a claim at age 12 has until age 20 to sue. The 15-year ultimate period still runs from the date of the act or omission.
For personal injury claims arising from a municipality's failure to maintain a highway or bridge, written notice must be given to the municipality within 10 days of the injury. This is separate from the limitation period — failure to give notice within 10 days may bar the claim unless the court grants relief. The 2-year limitation period for commencing the action still applies.
A construction lien must be preserved within 60 days of the date of last supply of services or materials. An action to enforce the lien must be commenced within 2 years of the date the lien was preserved. The basic Limitations Act periods apply as backstops.
There is no limitation period for claims based on sexual assault or sexual misconduct. A plaintiff may commence an action at any time regardless of when the assault occurred. The discovery rule and ultimate limitation period do not apply. This also applies to claims arising from sexual exploitation of a minor by a person in a position of trust.
For defamation in a newspaper or broadcast: written notice must be given to the defendant within 6 weeks of the publication coming to the plaintiff's knowledge. The action must be commenced within 3 months of serving the notice. For defamation not in a newspaper or broadcast, the general 2-year Limitations Act period applies.
Disclaimer: This is a reference guide for Ontario lawyers and is not legal advice. Limitation periods are complex — always verify against current legislation and case law, and consult with a colleague if in doubt. Nothing in this guide creates a lawyer-client relationship.
Enter the incident date and select the case type. Get every applicable limitation period instantly — with citations, days remaining, and a one-click button to add the calculated date as a tracked deadline in Atticus. No login required for the calculator.
Yes. The 2-year basic limitation period starts on the date the claim was 'discovered' under Limitations Act, 2002, s. 5. Discovery means the day the claimant first knew or ought reasonably to have known: (a) that the injury, loss, or damage occurred; (b) that it was caused by an act or omission of the person against whom the claim is made; (c) that the act or omission was that of the person against whom the claim is made; and (d) that a proceeding would be an appropriate means to seek to remedy it. In many cases — especially latent injury cases — the discovery date may be later than the date of the incident.
Yes. Parties can agree in writing to extend or suspend a limitation period under Limitations Act, 2002, s. 22. Such agreements are enforceable. However, parties cannot shorten a limitation period by agreement for consumer claims. For commercial matters, parties often include limitation period clauses in contracts — these must be carefully reviewed.
If a limitation period expires before the claim is commenced, the defendant can raise the limitation period as a complete defence. The claim will typically be dismissed. The plaintiff may have a claim against their lawyer for missing the deadline — this is one of the most common sources of legal malpractice claims in Ontario. This is why tracking limitation periods diligently, including using tools like the Atticus calculator, is essential.
The Atticus calculator at getatticus.ca/calculator allows you to enter both an incident date and a discovery date when they differ. The calculator will show both the period starting from the incident date and from the discovery date, and flag whichever produces the earlier expiry date. The ultimate 15-year period is always calculated from the incident date regardless of discovery.