Rule 17.Parties plaintiff and defendant

Part IV: Parties · Last amended May 1, 2014 · Last verified July 13, 2026

In one sentenceRule 17 requires every lawsuit to be filed in the name of the person who holds the legal claim, and spells out how minors, incompetent persons, and unincorporated groups sue and get sued.

Full Text of Rule 17

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

(a) Real party in interest. Every action shall be prosecuted in the name of the real party in interest. An executor, administrator, guardian, bailee, trustee of an express trust, a party with whom or in whose name a contract has been made for the benefit of another, or a party authorized by statute may sue in that person’s name without joining the party for whose benefit the action is brought; and when a statute so provides, an action for the use or benefit of another shall be brought in the name of the state of Utah. No action shall be dismissed on the ground that it is not prosecuted in the name of the real party in interest until a reasonable time has been allowed after objection for ratification of commencement of the action by, or joinder or substitution of, the real party in interest; and such ratification, joinder, or substitution shall have the same effect as if the action had been commenced in the name of the real party in interest.

(b) Minors or incompetent persons. An unemancipated minor or an insane or incompetent person who is a party must appear either by a general guardian or by a guardian ad litem appointed in the particular case by the court in which the action is pending. A guardian ad litem may be appointed in any case when it is deemed by the court in which the action or proceeding is prosecuted expedient to represent the minor, insane or incompetent person in the action or proceeding, notwithstanding that the person may have a general guardian and may have appeared by the guardian. In an action in rem it shall not be necessary to appoint a guardian ad litem for any unknown party who might be a minor or an incompetent person.

(1) When the minor is plaintiff, upon the application of the minor, if the minor is of the age of fourteen years, or if under that age, upon the application of a relative or friend of the minor.

(2) When the minor is defendant, upon the application of the minor if the minor is of the age of fourteen years and applies within 21 days after the service of the summons, or if under that age or if the minor neglects so to apply, then upon the application of a relative or friend of the minor, or of any other party to the action.

(3) When a minor defendant resides out of this state, the plaintiff, upon motion therefor, shall be entitled to an order designating some suitable person to be guardian ad litem for the minor defendant, unless the defendant or someone in behalf of the defendant within 21 days after service of notice of such motion shall cause to be appointed a guardian for such minor. Service of such notice may be made upon the defendant’s general or testamentary guardian located in the defendant’s state; if there is none, such notice, together with the summons in the action, shall be served in the manner provided for publication of summons upon such minor, if over fourteen years of age, or, if under fourteen years of age, by such service on the person with whom the minor resides. The guardian ad litem for such nonresident minor defendant shall have 21 days after appointment in which to plead to the action.

(4) When an insane or incompetent person is a party to an action or proceeding, upon the application of a relative or friend of such insane or incompetent person, or of any other party to the action or proceeding.

(d) Associates may sue or be sued by common name. When two or more persons associated in any business either as a joint-stock company, a partnership or other association, not a corporation, transact such business under a common name, whether it comprises the names of such associates or not, they may sue or be sued by such common name. Any judgment obtained against the association shall bind the joint property of all the associates in the same manner as if all had been named parties and had been sued upon their joint liability. The separate property of an individual member of the association may not be bound by the judgment unless the member is named as a party and the court acquires jurisdiction over the member.

(e) Action against a nonresident doing business in this state. When a nonresident person is associated in and conducts business within the state of Utah in one or more places in that person’s own name or a common trade name, and the business is conducted under the supervision of a manager, superintendent or agent the person may be sued in the person’s name in any action arising out of the conduct of the business.

(f) As used in these rules, the term plaintiff shall include a petitioner, and the term defendant shall include a respondent.

Amendment History

Amended effective September 1, 1991; April 1, 1998; April 1, 2007; May 1, 2014.

Advisory Committee Notes

Paragraph (d) has been changed to conform to the holding in Cottonwood Mall Co. v. Sine, 767 P.2d 499 (Utah 1988), which allows an unincorporated association to sue in its own name. The rule continues to allow an unincorporated association to be sued in its own name. The final sentence of paragraph (d) was added to confirm that the separate property of an individual member of an association may not be bound by the judgment unless the member is made a party.

Technical changes in all paragraphs of the rule make the terminology gender neutral. In part (c) the word “minor” has replaced the word “infant,” in order to maintain consistency with recent changes made in Rule 4(e)(2). In Rule 4 an infant is defined as a person under the age of 14 years, whereas the intent of Rule 17(c) is to include persons under the age of 18 years.

Plain-English Summary

A lawsuit belongs to the person whose right was violated, not to a lawyer, a relative, or anyone else who happens to care about the outcome. Rule 17 calls that person the real party in interest and requires the case to run in their name. It carves out exceptions for people who legitimately act for someone else — an executor, administrator, guardian, trustee of an express trust, or a party who signed a contract on another person's behalf — letting them sue without dragging the beneficiary into the caption. If a case gets filed in the wrong name, the court will not throw it out on the spot. The rule gives the parties a reasonable window to fix the problem, whether by ratifying the filing, joining the right party, or substituting them in, and once that happens the case proceeds as if it had been filed correctly from the start.

Children and people who cannot manage their own affairs need a guardian ad litem to appear for them, and Rule 17 lays out exactly how courts appoint one, depending on whether the minor is fourteen or older, whether they are suing or being sued, and whether an out-of-state minor defendant needs special handling. The rule also lets partnerships and other unincorporated associations sue or be sued under their common business name, though a judgment against the group only reaches an individual member's own property if that person was named and served personally. A nonresident who runs a business in Utah under their own name or a trade name can be sued here over claims arising from that business. Finally, wherever the rules say "plaintiff" or "defendant," that also covers a petitioner or respondent in other kinds of proceedings.

Frequently Asked Questions

What does "real party in interest" mean?

It means the person who owns the claim — the one entitled to the money or relief if the case wins. Rule 17 requires that person's name on the case, though people who legally act for others, like an executor or trustee, can sue in their own name without naming the person they represent.

Can a case get dismissed because it was filed in the wrong person's name?

Not right away. Rule 17 gives the parties a reasonable time after someone objects to fix the problem — by ratifying the filing, adding the real party in interest, or substituting them in. Once that happens, the case counts as if it had been filed correctly from the beginning.

Who appoints a guardian ad litem for a child or an incompetent person, and how?

The court does, on application. If the minor is fourteen or older, the minor (or, if the minor is a defendant, the minor or another party) applies directly. Below that age, a relative, friend, or other party to the case applies on the minor's behalf. Courts follow a similar process for a person who is insane or incompetent.

Can a partnership or other unincorporated group sue or be sued under its business name?

Yes. Rule 17 lets an unincorporated association — a partnership, joint-stock company, or similar group — sue or be sued using its common business name instead of listing every member individually. A judgment against the group binds the members' joint property, but it reaches an individual member's separate property only if that member was named as a party and served.

What happens if a minor defendant lives out of state?

The plaintiff can ask the court to designate someone to serve as guardian ad litem for that minor, unless the defendant's side arranges for a guardian within 21 days after being notified of the motion. Notice goes to the minor's out-of-state guardian if one exists, or otherwise is served the way a summons is served by publication.

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

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