Class certification
Class certification is the judge's ruling that a lawsuit can go forward as a class action on behalf of a defined group of people.
Also called: certification, certified class, certify a class
Class certification is the judge's ruling that a lawsuit can go forward as a class action on behalf of a defined group of people.
What it means
Class certification is the court order that lets a lawsuit proceed as a class action. Until a judge certifies a class, the case belongs only to the named plaintiffs. The order defines the class and the claims, and it appoints class counsel.
To certify, the judge must find that the four Rule 23(a) tests are met: numerosity, commonality, typicality and adequacy. The case must also fit one of the Rule 23(b) types. For money damages, that is usually Rule 23(b)(3), which requires that common questions predominate and that a class action is the better way to resolve the dispute. The plaintiffs must prove these points, not just allege them.
A class can also be certified for settlement only, when the judge first reviews a deal. Either way, the order can be changed before final judgment, and a party can ask a court of appeals for permission to appeal it within 14 days.
What it means for you
Certification doesn't decide who is right, and it doesn't put money in anyone's hands. It decides that the case can go forward for the whole group. After it, class members get notice and a chance to opt out, and the case usually heads toward settlement or trial. If a court refuses to certify, the case generally can't continue as a class action. People who would have been class members may still be able to sue on their own. Time limits can matter then, so see tolling. A settlement notice often says the class is certified "for settlement purposes."
Example
Say customers sue over a hidden fee. The company asks the judge to throw the case out and loses. The customers then ask the judge to certify a class of everyone charged the fee. After reviewing the evidence, the judge certifies the class, names class counsel and orders notice to be sent. Settlement talks follow. If the judge had refused, the case would have stayed one customer's lawsuit.
FAQ
No. Certification only decides that the case can go forward on behalf of a group. The judge does not decide whether the company did anything wrong, and no one is owed money until there is a settlement or a judgment.
Yes. Under Rule 23(c)(1)(C), an order granting or denying certification can be changed before final judgment. A court of appeals may also agree to review it if a party asks for permission within 14 days.
Related terms
- Fed. R. Civ. P. 23, Class Actions (Cornell Legal Information Institute)
- Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338 (2011) (U.S. Reports, Library of Congress)
Updated Oct 18, 2026. Plain-English definitions for general information — not legal or tax advice.