Fed. R. Civ. P. 23 — Class Actions
Last verified: May 19, 2026 · U.S. Courts — FRCP.
Rule Text — Key Provisions
(a) Prerequisites. A class action requires: (1) numerosity, (2) commonality, (3) typicality, and (4) adequacy of representation.
(b) Types. 23(b)(1) risk of inconsistent adjudications; 23(b)(2) injunctive/declaratory relief; 23(b)(3) damages class where common questions predominate and a class action is superior.
(c)(2)(B) requires the best notice practicable for damages classes — individual notice to identifiable members. (h) Court must approve attorney fees from a common fund.
Full text: law.cornell.edu/rules/frcp/rule_23.
Plain English
A class action lets one person sue on behalf of thousands. Five hoops: numerosity, commonality, typicality, adequacy, and one of three 23(b) pathways. The real fight is certification — grant it and settlement leverage shifts dramatically; deny it and the case ends.
Key Cases & Authority
- Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338 (2011) — Tightened commonality. Killed nationwide employment-discrimination classes.
- Amchem Products v. Windsor, 521 U.S. 591 (1997) — Predominance requires common issues actually predominate; settlement classes still meet Rule 23.
- Ortiz v. Fibreboard Corp., 527 U.S. 815 (1999) — Limits on 23(b)(1)(B) limited-fund classes.
- Comcast Corp. v. Behrend, 569 U.S. 27 (2013) — Damages model must tie to liability theory at certification.
- Tyson Foods v. Bouaphakeo, 577 U.S. 442 (2016) — Representative statistical evidence permitted when individual proof would be the same.
- Standard Fire Ins. Co. v. Knowles, 568 U.S. 588 (2013) — Damages stipulations cannot defeat CAFA jurisdiction.
Florida Parallel
Fla. R. Civ. P. 1.220 — structurally similar; certification rarer in state court. Most class actions of size end up in federal court under CAFA (28 U.S.C. § 1332(d)).
About this rule walkthrough
Part of The Federal Rule Book, hosted by John M. Phillips — Board Certified Civil Trial Lawyer, Court TV analyst, admitted in 8 states + 9 federal districts + SCOTUS.
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Educational only — not legal advice.
Rule Text (verbatim from the Florida Supreme Court)
(a) Prerequisites. One or more members of a class may sue or be sued as representative parties on behalf of all members 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) A class action may be maintained if Rule 23(a) is satisfied AND: 23(b)(1) separate actions would create a risk of inconsistent adjudications or impair absent members’ interests; 23(b)(2) the party opposing the class has acted on grounds generally applicable to the class, making injunctive or declaratory relief appropriate; or 23(b)(3) common questions predominate and a class action is superior — the damages class.
(h) The court must approve attorney’s fees and may award reasonable fees from a common fund.
Educational reference. This page summarizes a Federal Rule of Civil Procedure for educational purposes. It is not legal advice. Federal procedural rules can change — always verify the current text at uscourts.gov before relying on this summary in any case.
What this rule means in plain English
A class action lets one person sue on behalf of thousands. Rule 23 sets five tests: numerosity, commonality, typicality, adequacy, and one of three pathways under 23(b). The real fight is certification. If the court certifies, settlement leverage shifts dramatically; if denied, the case essentially ends.