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Rule 23.Class actions

Part IV: Parties · Not amended since adoption on record · Last verified July 13, 2026

In one sentenceRule 23 lets one or a few people sue, or get sued, on behalf of an entire group with the same kind of claim, but only after the case clears strict requirements on class size, shared questions, and adequate representation.

Full Text of Rule 23

Text sizeJump to: (a) (b) (c) (d) (e)

(a) Prerequisites to a class action. One or more members of a class may sue or be sued as representative parties on behalf of all only if (1) the class is so numerous that joinder of all members is impracticable, (2) there are questions of law or fact common to the class, (3) the claims or defenses of the representative parties are typical of the claims or defenses of the class, and (4) the representative parties will fairly and adequately protect the interests of the class.
(b) Class actions maintainable. An action may be maintained as a class action if the prerequisites of Subdivision (a) are satisfied, and in addition:
(1) The prosecution of separate actions by or against individual members of the class would create a risk of:
(A) inconsistent or varying adjudications with respect to individual members of the class which would establish incompatible standards of conduct for the party opposing the class, or
(B) adjudications with respect to individual members of the class which would as a practical matter be dispositive of the interests of the other members not parties to the adjudications or substantially impair or impede their ability to protect their interests; or
(2) The party opposing the class has acted or refused to act on grounds generally applicable to the class, thereby making appropriate final injunctive relief or corresponding declaratory relief with respect to the class as a whole; or
(3) The court finds that the questions of law or fact common to the members of the class predominate over any questions affecting only individual members, and that a class action is superior to other available methods for the fair and efficient adjudication of the controversy. The matters pertinent to the findings include: (A) the interest of members of the class in individually controlling the prosecution or defense of separate actions; (B) the extent and nature of any litigation concerning the controversy already commenced by or against members of the class; (C) the desirability or undesirability of concentrating the litigation of the claims in the particular forum; (D) the difficulties likely to be encountered in the management of a class action.
(c) Determination by order whether class action to be maintained; notice; judgment; actions conducted partially as class actions.
(1) As soon as practicable after the commencement of an action brought as a class action, the court shall determine by order whether it is to be maintained. An order under this subdivision may be conditional, and may be altered or amended before the decision on the merits.
(2) In any class action maintained under Subdivision (b)(3), the court shall direct to the members of the class the best notice practicable under the circumstances, including individual notice to all members who can be identified through reasonable effort. The notice shall advise each member that (A) the court will exclude him from the class if he so requests by a specified date; (B) the judgment, whether favorable or not, will include all members who do not request exclusion; and (C) any member who does not request exclusion may, if he desires, enter an appearance through his counsel.
(3) The judgment in an action maintained as a class action under Subdivision (b)(1) or (b)(2), whether or not favorable to the class, shall include and describe those whom the court finds to be members of the class. The judgment in an action maintained as a class action under Subdivision (b)(3), whether or not favorable to the class, shall include and specify or describe those to whom the notice provided in Subdivision (c)(2) was directed, and who have not requested exclusion, and whom the court finds to be members of the class.
(4) When appropriate (A) an action may be brought or maintained as a class action with respect to particular issues, or (B) a class may be divided into subclasses and each subclass treated as a class, and the provisions of this rule shall then be construed and applied accordingly.
(d) Orders in conduct of actions. In the conduct of actions to which this rule applies, the court may make appropriate orders: (1) determining the course of proceedings or prescribing measures to prevent undue repetition or complication in the presentation of evidence or argument; (2) requiring, for the protection of the members of the class or otherwise for the fair conduct of the action, that notice be given in such manner as the court may direct to some or all of the members of any step in the action, or of the proposed extent of the judgment, or of the opportunity of members to signify whether they consider the representation fair and adequate, to intervene and present claims or defenses, or otherwise to come into the action; (3) imposing conditions on the representative parties or on intervenors; (4) requiring that the pleadings be amended to eliminate therefrom allegations as to representation of absent persons, and that the action proceed accordingly; (5) dealing with similar procedural matters. The orders may be combined with an order under Rule 16, and may be altered or amended as may be desirable from time to time.
(e) Dismissal or compromise. A class action shall not be dismissed or compromised without the approval of the court, and notice of the proposed dismissal or compromise shall be given to all members of the class in such manner as the court directs.

Plain-English Summary

A class action lets a handful of named plaintiffs stand in for a much larger group of people whose claims are similar enough to resolve together. Rule 23 does not hand that power out automatically. Every proposed class action must first clear four prerequisites: the class has to be so large that joining every member individually would be impracticable; there must be questions of law or fact common to the class; the named representatives' claims or defenses must be typical of the class as a whole; and those representatives must be capable of protecting the class's interests adequately throughout the case. A case that fails any one of these four requirements cannot proceed as a class action.

Clearing those four hurdles is only the first step — the case must also fit one of three categories in Rule 23(b). The first covers situations where separate lawsuits by individual class members would risk inconsistent rulings that create conflicting standards of conduct, or would as a practical matter decide the rights of class members who are not even part of those separate suits. The second covers cases where the opposing party has acted, or refused to act, on grounds that apply to the whole class, making class-wide injunctive or declaratory relief the appropriate remedy — common in civil-rights and consumer-protection style disputes. The third and most commonly litigated category requires the court to find that common questions predominate over questions affecting only individual members, and that a class action is the superior way to resolve the controversy, weighing factors like how much individual class members want to control their own litigation, how much related litigation already exists, whether concentrating the case in one court makes sense, and how hard the class action will be to manage.

Once a class action is filed, the court has to decide as soon as practical whether the case will proceed as a class action, and that certification decision can be conditional and revised before the case is decided on the merits. For the predominance-and-superiority category under Rule 23(b)(3), the court must send the best notice practical under the circumstances, including individual notice to anyone who can be identified through reasonable effort, telling class members they can opt out by a set date, that the judgment will bind everyone who does not opt out, and that they can appear through their own counsel if they choose. Whatever the outcome, the final judgment has to identify who counts as a class member, and courts can certify a class on particular issues only, or split a class into subclasses handled separately, when that fits the case better. Along the way, the court can issue case-management orders covering everything from how evidence gets presented to what notice goes out and what conditions apply to the representatives. Because a class action affects people who are not directly managing their own case, Rule 23(e) requires court approval before a class action can be dismissed or settled, and notice of any proposed dismissal or settlement has to go out to the class first.

Frequently Asked Questions

What four requirements does every proposed class action have to meet?

The class must be too numerous for individual joinder to be practical, there must be questions of law or fact common to the class, the representatives' claims or defenses must be typical of the class, and the representatives must be able to protect the class's interests adequately. All four have to be satisfied before the case can even reach the next step.

What's the difference between the three types of class actions under Rule 23(b)?

The first type applies when separate lawsuits would risk inconsistent rulings or effectively decide absent members' rights. The second applies when the opposing party acted on grounds affecting the whole class, making class-wide injunctive or declaratory relief appropriate. The third, and most common, requires common questions to predominate over individual ones and a class action to be the best way to resolve the dispute.

How do class members find out about the case and their right to opt out?

In a Rule 23(b)(3) predominance-type class action, the court sends the best notice practical under the circumstances, including individual notice to anyone identifiable through reasonable effort. The notice tells members how to opt out by a specific date, warns that staying in means the judgment binds them either way, and lets them appear through their own lawyer if they want.

Can a class action be settled or dismissed without the court signing off?

No. Rule 23(e) requires court approval before a class action can be dismissed or compromised, and notice of the proposed dismissal or settlement has to reach the class first.

Can a court split a class action into smaller pieces?

Yes. Rule 23(c)(4) lets a court certify a class action on particular issues only, or divide the class into subclasses that get treated as separate classes when that better fits the case.

Does the court have to formally decide whether a case can proceed as a class action?

Yes. Rule 23(c)(1) requires the court to decide as soon as practical after the case is filed whether it will be maintained as a class action. That decision can be conditional and can be changed later, before the case is resolved on the merits.

Source & verification. Rule text, Advisory Committee Notes, and amendment history are reproduced verbatim from the Utah Rules of Civil Procedure, adopted by the Utah Supreme Court. Last verified July 13, 2026. · Official source
Also known as: class action lawsuitclass certification requirementssuing on behalf of a groupopt out of class actionnumerosity commonality typicality adequacyclass action settlement approval