Misjoinder of parties is not a ground for dismissing an action. On motion or on its own, the court may at any time, on just terms, add or drop a party. The court may also sever any claim against a party.
Rule 21.Misjoinder and nonjoinder of parties
Group IV: Parties · Last amended March 1, 2017 · Last verified July 14, 2026
In one sentenceRule 21 says that suing the wrong mix of parties is never grounds to throw out a case outright, since the court can add, drop, or sever parties on its own or on motion at any stage.
Full Text of Rule 21
Amendment History
Added February 2, 2017, effective March 1, 2017.
Plain-English Summary
Rule 21 removes a once-common trap: getting the parties wrong doesn't sink a lawsuit. Even if the plaintiff sued the wrong combination of people, or left someone out who should have been included, that mistake is not grounds for dismissal on its own.
Instead, the court has ongoing authority to fix the party lineup. On a motion or on its own initiative, at any point in the case and on terms it considers fair, the court can add a missing party, drop one that doesn't belong, or sever a claim against a particular party into its own separate proceeding.
Frequently Asked Questions
Can a case be dismissed just because the wrong parties were joined?
No. Rule 21 says misjoinder is never, by itself, a ground for dismissing an action.
Can the court add or remove a party without anyone asking?
Yes. The court can act on a motion or on its own initiative, at any point in the case, to add a missing party or drop one that does not belong.
What does it mean for a court to sever a claim?
Severing a claim splits it off from the rest of the case so it proceeds as its own separate action, usually against or involving a particular party.
Is there a deadline for fixing misjoined parties?
No fixed deadline. Rule 21 lets the court add, drop, or sever parties at any time, as long as it does so on just terms.
What is the difference between dropping a party and severing a claim?
Dropping a party removes them from the case entirely. Severing a claim keeps the claim alive but separates it into its own proceeding, often while other parties or claims remain in the original case.
Source & verification. Rule text and amendment history are
reproduced verbatim from the Wyoming Rules of Civil Procedure, adopted by the
Supreme Court of Wyoming. Last verified July 14, 2026. ·
Official source
Also known as: misjoinder of parties wyomingwrong party lawsuit fixsever claims ruleadd or drop party motion