Title III: Pleadings; Motions; Scheduling · Last amended July 1, 2016 · Last verified July 14, 2026
In one sentenceRule 14 lets a defending party bring a nonparty into the case as a third-party defendant when that nonparty may owe it for all or part of the plaintiff's claim, and sets out the resulting claims and defenses among plaintiff, defendant, and third-party defendant.
(a)When a defending party may bring in a third party.
(1)Timing of the summons and complaint. A defending party may, as third-party plaintiff, serve a summons and complaint on a nonparty who is or may be liable to it for all or part of the claim against it. But the third-party plaintiff must, by motion, obtain the court's leave if it files the third-party complaint more than 14 days after serving its original answer.
(2)Third-party defendant's claims and defenses. The person served with the summons and third- party complaint, the "third-party defendant":
(A)must assert any defense against the third-party plaintiff's claim under Rule 12;
(B)must assert any counterclaim against the third-party plaintiff under Rule 13(a), and may assert any counterclaim against the third-party plaintiff under Rule 13(b) or any crossclaim against another third-party defendant under Rule 13(g);
(C)may assert against the plaintiff any defense that the third-party plaintiff has to the plaintiff's claim; and
(D)may also assert against the plaintiff any claim arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff.
(3)Plaintiff's claims against a third-party defendant. The plaintiff may assert against the third-party defendant any claim arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff. The third-party defendant must then assert any defense under Rule 12 and any counterclaim under Rule 13(a), and may assert any counterclaim under Rule 13(b) or any crossclaim under Rule 13(g).
(4)Motion to strike, sever, or try separately. Any party may move to strike the third-party claim, to sever it, or to try it separately.
(5)Third-party defendant's claim against a nonparty. A third-party defendant may proceed under this rule against a nonparty who is or may be liable to the third-party defendant for all or part of any claim against it.
(b)When a plaintiff may bring in a third party. When a claim is asserted against a plaintiff, the plaintiff may bring in a third party if this rule would allow a defendant to do so.
Amendment History
(Adopted March 1, 2016, effective July 1, 2016.)
Plain-English Summary
Rule 14 gives a defending party a way to pull a nonparty into an ongoing lawsuit, rather than filing a separate action, when that outsider may end up owing the defendant for some or all of what the plaintiff is claiming. The defending party becomes a third-party plaintiff and serves a summons and complaint on the nonparty. Doing this within 14 days of serving the original answer requires no permission, but after that window the third-party plaintiff needs the court's leave.
Once served, the third-party defendant steps into a web of claims and defenses defined by the rule: it must raise defenses under Rule 12 and any compulsory counterclaim under Rule 13(a) against the third-party plaintiff, may raise permissive counterclaims or crossclaims against other third-party defendants, may assert against the plaintiff any defense the third-party plaintiff has, and may bring its own claim against the plaintiff arising from the same transaction or occurrence. The plaintiff, in turn, may assert a related claim directly against the third-party defendant, who then owes the same defense and counterclaim obligations back to the plaintiff. Any party can move to strike, sever, or separately try the third-party claim, and a third-party defendant facing its own liability exposure can repeat the same process against a further nonparty. A plaintiff who becomes a defendant to a counterclaim gets the same third-party practice available to an original defendant.
Frequently Asked Questions
What is a third-party complaint under Rule 14?
It is a complaint a defending party files against someone not yet in the case, called the third-party defendant, when that person or entity may be liable to the defending party for all or part of what the plaintiff is claiming. This lets the whole dispute be resolved in one lawsuit.
Do I need the court's permission to file a third-party complaint?
Only if you wait. Rule 14(a)(1) lets a defending party serve a third-party complaint without leave of court within 14 days of serving its original answer; after that, the party must ask the court for permission.
What can a third-party defendant do once brought into the case?
The third-party defendant must raise its defenses under Rule 12 and any compulsory counterclaim under Rule 13(a) against the party that brought it in, and it may also raise permissive counterclaims, crossclaims against other third-party defendants, defenses the original defendant has against the plaintiff, and its own related claim against the plaintiff.
Can the plaintiff sue the third-party defendant directly?
Yes. Rule 14(a)(3) lets the plaintiff assert a claim against the third-party defendant if it arises from the same transaction or occurrence as the plaintiff's claim against the original defendant. The third-party defendant then owes the plaintiff the same Rule 12 and Rule 13 obligations.
Can a plaintiff use Rule 14 too, not just a defendant?
Yes. Rule 14(b) allows a plaintiff who is facing a counterclaim to bring in a third party under the same procedure available to a defendant, treating the plaintiff as the defending party for that purpose.
Source & verification. Rule text
are reproduced verbatim from the Idaho Rules of Civil Procedure, adopted by the
Supreme Court of Idaho. Last verified July 14, 2026. ·
Official source
Also known as:third party complaint Idahoimpleader rulebringing in a third party defendantthird party plaintiff claimindemnity claim third party