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 2017 · Last verified July 14, 2026
In one sentenceRule 21 makes clear that joining the wrong parties, or leaving out the right ones, is never by itself a reason to throw out a case — the court can add or drop parties, or sever claims, on motion or on its own, at any time and on just terms.
Full Text of Rule 21
Comments
2017 Amendments:
Rule 21 has been amended consistent with the 2007 stylistic changes to Federal Rule of Civil Procedure 21.
Comment:
Identical to Federal Rule of Civil Procedure 21.
Plain-English Summary
Rule 21 states its core principle in one sentence: misjoinder of parties is not a ground for dismissing an action. A case that has drawn in the wrong party, or too many parties, does not have to end over that mistake. Instead, the court can fix the problem directly — on motion by any party, or on its own initiative, at any point in the litigation and on terms that are fair to everyone affected, the court may add or drop a party.
The rule also gives the court authority to sever any claim against a party. Severance lets the court split off a claim that does not belong bundled with the rest of the case — for example because it needs its own schedule, its own discovery, or its own trial — without disturbing the remainder of the litigation.
Read together with Rules 19 and 20, Rule 21 supplies the remedy: those rules describe who should or may be joined, and Rule 21 confirms that getting party joinder wrong is a problem to be corrected, not a reason to dismiss the case outright.
Frequently Asked Questions
Can my case be thrown out because I sued the wrong person or left someone out?
No. Rule 21 states directly that misjoinder of parties is not a ground for dismissing an action. The remedy is to add or drop the party, not to dismiss the case.
Who can ask the court to add or drop a party under Rule 21?
Any party can move for that relief, and the court can also act on its own without waiting for a motion. Rule 21 gives the court authority to do so at any time in the case.
Is there a deadline for fixing a misjoinder problem?
Rule 21 does not set a specific deadline. It authorizes the court to add or drop a party on just terms at any time, which gives the court flexibility to correct the problem whenever it comes to light.
What does it mean for the court to "sever" a claim under Rule 21?
Severance separates a particular claim against a party from the rest of the case so it can proceed on its own, which the court may use when that claim needs different handling than the claims that remain.
Does Rule 21 apply to both adding and dropping parties?
Yes. Rule 21 authorizes the court to add a party who should be in the case as well as drop a party who was joined improperly, using the same just-terms standard for either action.
Source & verification. Rule text and official Comments are
reproduced verbatim from the District of Columbia Superior Court Rules of Civil
Procedure, adopted by the Superior Court of the District of Columbia. Last verified July 14, 2026.
· Official source
Also known as: dc misjoinder of partiesadding or dropping a party dc lawsuitsever claims dc superior courtwrong defendant dismissal dcrule 21 dc civil procedure