A class action in Ontario is governed by the Class Proceedings Act, 1992 and allows a representative plaintiff to sue on behalf of a defined class of people with a common legal claim against the same defendant. The case must first be certified by a court as a class proceeding, a procedural step assessing whether the claim is suitable to proceed collectively — it is not a decision on whether the claim will ultimately succeed. For claims started on or after October 1, 2020, a stricter test applies, requiring that a class proceeding be the superior method of resolving the claims and that common issues predominate over individual ones. Being part of a class is usually automatic unless a class member chooses to opt out.
- A class action requires certification by a court before it can proceed as a class proceeding — this is a procedural gateway, not a ruling on the merits.
- For claims started on or after October 1, 2020, a stricter certification test applies, requiring the class action to be the superior method of resolving the claims.
- Common issues must generally predominate over individual issues under the current test — a meaningful change from the older, more permissive standard.
- Certification cannot be refused solely because damages would need individual assessment, because claims arise from separate contracts, or because class members seek different remedies.
- Class members are usually included automatically unless they affirmatively choose to opt out of the proceeding.
- Certification itself can take years, and increasingly faces pre-certification motions to narrow or dismiss claims before the certification motion is even heard.
The Short Answer
A class action in Ontario, governed by the Class Proceedings Act, 1992, lets a representative plaintiff pursue a claim on behalf of a larger class of people who share a common legal grievance against the same defendant. Before it can actually proceed as a class action, a court must certify it — a procedural gateway, not a decision on whether the underlying claim will ultimately succeed.
What a Class Action Actually Is
Instead of requiring hundreds or thousands of individuals to each bring their own separate lawsuit over the same underlying conduct — a defective product, a data breach, a pricing practice — a class action resolves the common issues once, in a single proceeding, with a representative plaintiff standing in for the class. This is significantly more efficient than the alternative, both for the court system and for class members whose individual claims might be too small to justify suing on their own, a consideration that also comes up in deciding whether to sue in Small Claims Court or Superior Court for an individual claim.
Certification: The Essential Gateway
No class action can actually proceed as one until a court certifies it. At certification, the court assesses specific statutory criteria — including whether the pleadings disclose a valid cause of action, whether there is an identifiable class, whether there are common issues, and whether a representative plaintiff with a workable litigation plan exists — without deciding whether the claim itself will ultimately win or lose.
A certified class action can still lose at trial or on a later motion. An action that is refused certification does not mean the underlying claims lacked merit — it means a court decided a class proceeding specifically was not the right vehicle for them.
The 2020 Changes to the Test
For actions commenced on or after October 1, 2020, Ontario adopted a materially stricter certification test. A class proceeding must now be the superior method of resolving the class members' claims, and common issues must predominate over individual ones — replacing the older, more permissive “preferable procedure” standard. This change has led to more frequent pre-certification motions by defendants seeking to dismiss or narrow claims before certification is even argued.
What Can't Defeat Certification Alone
The Act specifically protects against certain narrow objections being used to block certification on their own: a court cannot refuse certification solely because individual damages assessment will eventually be required, because the claims arise from separate contracts between class members and the defendant, or because class members are seeking different forms of relief. These factors can still be relevant to the overall analysis, but none of them is a complete bar by itself.
What Being a Class Member Means
If you fall within a certified class definition, you are generally included automatically, without needing to take any action, unless you choose to opt out within a specified period. Opting out preserves your right to pursue your own individual claim separately, but also means you will not share in any settlement or judgment obtained by the class. Most class members do not retain their own lawyer, since representative counsel conducts the litigation on behalf of the entire class. Class proceedings alleging fraud sometimes overlap with the issues covered in our guide on civil fraud claims in Ontario, and widespread reputational harm can sometimes raise defamation considerations as well.
What to Do If You Believe You Have a Class Claim
If you believe you, or a group of people in a similar position, have been affected by the same conduct from the same defendant, get advice on whether a class proceeding — or an individual claim — is the better fit, considering the certification test's current, stricter standard. Certification motions, like summary judgment motions, depend heavily on a well-developed evidentiary record, often built through examinations for discovery. Where the underlying conduct involves hidden assets or anonymous wrongdoers, our guides on Mareva injunctions and Anton Piller orders and Norwich orders may also be relevant before a claim can even be properly framed. Call 416-274-2222 for a free, confidential consultation.
Frequently Asked Questions
An ordinary lawsuit involves one plaintiff suing over their own individual claim. A class action allows one or a few representative plaintiffs to sue on behalf of a larger group of people who share a common legal claim against the same defendant, resolving common issues in a single proceeding rather than requiring each person to sue individually.
Certification is the court's decision on whether a proposed class proceeding should actually be allowed to proceed collectively, assessed against specific statutory criteria. It is a procedural gateway, not a decision on whether the underlying claim will succeed — a case can be certified and still lose, or fail to be certified even with a potentially strong underlying claim.
For actions started on or after October 1, 2020, Ontario adopted a stricter test requiring that a class proceeding be the superior method of resolving the class members' claims, and that common issues predominate over individual issues — replacing the previously more permissive "preferable procedure" standard.
No. The legislation specifically provides that certification cannot be refused solely because individual damages assessment would be required, because the claims arise under separate contracts, or because class members seek different types of relief.
Generally no. Class membership is usually automatic for anyone who falls within the defined class, unless you choose to actively opt out of the proceeding, which preserves your right to pursue your own separate claim instead.
It varies significantly, but certification motions can take a long time to reach a hearing and decision — multi-year timelines are common, particularly as pre-certification motions to dismiss or narrow claims have become more frequent since the 2020 changes.
Often not necessary for a typical class member, since representative counsel handles the litigation on behalf of the class. However, if you have a potentially larger or distinct individual claim, or specific questions about your rights within the proceeding, independent advice can be worthwhile.