Rule 5.24.Joinder of persons claiming interest

Division 1. Family Rules · Chapter 2. Parties and Joinder of Parties · Article 2. Joinder of Parties · Last amended 2017 · Last verified September 10, 2026

In one sentenceRule 5.24 is the joinder rule: it sets out who may be brought into a family law case as a party, how to ask, and when the court must order it rather than merely may.

Full Text of Rule 5.24

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A person who claims or controls an interest in any matter subject to disposition in the proceeding may be joined as a party to the family law case only as provided in this chapter.

(a) Applicable rules

(1) All provisions of law relating to joinder of parties in civil actions generally apply to the joinder of a person as a party to a family law case, except as otherwise provided in this chapter.

(2) The law applicable to civil actions generally governs all pleadings, motions, and other matters pertaining to that portion of the proceeding as to which a claimant has been joined as a party to the proceeding in the same manner as if a separate action or proceeding not subject to these rules had been filed, except as otherwise provided in this chapter or by the court in which the proceeding is pending.

(b) “Claimant” defined

For purposes of this rule, a “claimant” is an individual or an entity joined or sought or seeking to be joined as a party to the family law proceeding.

(1) The petitioner or the respondent may apply to the court for an order joining a person as a party to the case who has or claims custody or physical control of any of the minor children subject to the action, or visitation rights with respect to such children, or who has in his or her possession or control or claims to own any property subject to the jurisdiction of the court in the proceeding.

(2) A person who has or claims custody or physical control of any of the minor children subject to the action, or visitation rights with respect to such children, may apply to the court for an order joining himself or herself as a party to the proceeding.

(3) A person served with an order temporarily restraining the use of property that is in his or her possession or control or that he or she claims to own, or affecting the custody of minor children subject to the action, or visitation rights with respect to such children, may apply to the court for an order joining himself or herself as a party to the proceeding.

(d) Form of joinder application

(1) All applications for joinder other than for an employee pension benefit plan must be made by serving and filing form a Notice of Motion and Declaration for Joinder (form FL-371). The hearing date must be less than 30 days from the date of filing the notice. The completed form must state with particularity the claimant’s interest in the proceeding and the relief sought by the applicant, and it must be accompanied by an appropriate pleading setting forth the claim as if it were asserted in a separate action or proceeding.

(2) A blank copy of Responsive Declaration to Motion for Joinder and Consent Order for Joinder (form FL-373) must be served with the Notice of Motion and accompanying pleading.

(e) Court order on joinder

(1) Mandatory joinder

(A) The court must order that a person be joined as a party to the proceeding if the court discovers that person has physical custody or claims custody or visitation rights with respect to any minor child of the marriage, domestic partnership, or to any minor child of the relationship.

(B) Before ordering the joinder of a grandparent of a minor child in the proceeding under Family Code section 3104, the court must take the actions described in section 3104(a).

(2) Permissive joinder The court may order that a person be joined as a party to the proceeding if the court finds that it would be appropriate to determine the particular issue in the proceeding and that the person to be joined as a party is either indispensable for the court to make an order about that issue or is necessary to the enforcement of any judgment rendered on that issue. In deciding whether it is appropriate to determine the particular issue in the proceeding, the court must consider its effect upon the proceeding, including:

(A) Whether resolving that issue will unduly delay the disposition of the proceeding;

(B) Whether other parties would need to be joined to make an effective judgment between the parties;

(D) Whether the joinder of a party to determine the particular issue will complicate, delay, or otherwise interfere with the effective disposition of the proceeding.

(3) Procedure upon joinder If the court orders that a person be joined as a party to the proceeding under this rule, the court must direct that a summons be issued on Summons (Joinder) (form FL-375) and that the claimant be served with a copy of Notice of Motion and Declaration for Joinder (form FL-371), the pleading attached thereto, the order of joinder, and the summons. The claimant has 30 days after service to file an appropriate response.

End

Plain-English Summary

A person who claims or controls an interest in something the court will dispose of can be joined — but only as this chapter allows. General civil joinder law applies except where this chapter provides otherwise, and once a claimant is joined, the portion of the case involving that claimant is litigated as though it were a separate civil action.

Three routes lead in. Either party may apply to join a person who has or claims custody or physical control of a minor child, or visitation rights, or who holds or claims to own property subject to the court’s jurisdiction. A person in that position may apply to join themselves. So may a person served with an order temporarily restraining the use of property in their possession or affecting custody or visitation.

The mechanics are form-driven and the timing is tight: the application goes on a Notice of Motion and Declaration for Joinder, the hearing date must be less than 30 days from filing, the completed form must state the claimant’s interest and the relief sought with particularity, and it must attach a pleading setting out the claim as though it were being filed on its own. A blank responsive declaration goes out with it.

Joinder is mandatory in one situation: the court must join a person it discovers has physical custody of, or claims custody or visitation rights to, a minor child of the marriage, partnership, or relationship. Otherwise it is permissive, and the court weighs whether resolving the issue in this case would delay the disposition, require still more parties, confuse the other issues, or otherwise interfere. When joinder is ordered, a joinder summons issues and the claimant has 30 days after service to respond.

Frequently Asked Questions

When must the court join someone to a family law case?

When it discovers that the person has physical custody of, or claims custody or visitation rights with respect to, a minor child of the marriage, domestic partnership, or relationship. Joinder is mandatory in that situation.

Can a grandparent be joined?

Yes, but before ordering joinder of a grandparent under Family Code section 3104 the court must first take the actions that section 3104(a) requires.

How soon must the joinder hearing be set?

Less than 30 days from the date the notice of motion is filed.

How long does a joined party have to respond?

30 days after service of the joinder summons, the notice of motion and its attached pleading, and the joinder order.

Amendment History

Rule 5.24 amended effective January 1, 2017; adopted effective January 1, 2013.

(Subd (e) amended effective January 1, 2017.)

Source & verification. Rule text is reproduced verbatim from the Judicial Council of California. Adopted by the Judicial Council of California. Last verified September 10, 2026. · Official source

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