As used in this title, the following terms have the following meanings:
§ 391.Definitions
Title 3a. Vexatious Litigants · Last amended 2023 · Last verified July 28, 2026
In one sentenceSection 391 defines the key terms for California's vexatious litigant statute: litigation, vexatious litigant through five specific categories, security, plaintiff, and defendant, that the rest of Title 3a builds on.
Full Text of § 391
(a) "Litigation" means any civil action or proceeding, commenced, maintained or pending in any state or federal court.
(b) "Vexatious litigant" means a person who does any of the following:
(1) In the immediately preceding seven-year period has commenced, prosecuted, or maintained in propria persona at least five litigations other than in a small claims court that have been (i) finally determined adversely to the person or (ii) unjustifiably permitted to remain pending at least two years without having been brought to trial or hearing.
(2) After a litigation has been finally determined against the person, repeatedly relitigates or attempts to relitigate, in propria persona, either (i) the validity of the determination against the same defendant or defendants as to whom the litigation was finally determined or (ii) the cause of action, claim, controversy, or any of the issues of fact or law, determined or concluded by the final determination against the same defendant or defendants as to whom the litigation was finally determined.
(3) In any litigation while acting in propria persona, repeatedly files unmeritorious motions, pleadings, or other papers, conducts unnecessary discovery, or engages in other tactics that are frivolous or solely intended to cause unnecessary delay.
(4) Has previously been declared to be a vexatious litigant by any state or federal court of record in any action or proceeding based upon the same or substantially similar facts, transaction, or occurrence.
(5) After being restrained pursuant to a restraining order issued after a hearing pursuant to Chapter 1 (commencing with Section 6300) of Part 4 of Division 10 of the Family Code, and while the restraining order is still in place, they commenced, prosecuted, or maintained one or more litigations against a person protected by the restraining order in this or any other court or jurisdiction that are determined to be meritless and caused the person protected by the order to be harassed or intimidated.
(c) "Security" means an undertaking to assure payment, to the party for whose benefit the undertaking is required to be furnished, of the party's reasonable expenses, including attorney's fees and not limited to taxable costs, incurred in or in connection with a litigation instituted, caused to be instituted, or maintained or caused to be maintained by a vexatious litigant.
(d) "Plaintiff" means the person who commences, institutes or maintains a litigation or causes it to be commenced, instituted or maintained, including an attorney at law acting in propria persona.
(e) "Defendant" means a person (including corporation, association, partnership and firm or governmental entity) against whom a litigation is brought or maintained or sought to be brought or maintained.
Plain-English Summary
Section 391 supplies the vocabulary for the whole vexatious litigant statute. “Litigation” means any civil action or proceeding pending in a state or federal court. “Plaintiff” and “defendant” carry their ordinary meaning but explicitly include a self-represented attorney and any kind of entity, including corporations, associations, partnerships, firms, and government bodies. “Security” is an undertaking that assures payment of the defendant's reasonable litigation expenses, including attorney's fees, not limited to costs that would ordinarily be taxable.
The heart of the section is subdivision (b)'s five-part definition of “vexatious litigant.” A person qualifies by: (1) commencing, prosecuting, or maintaining at least five litigations in propria persona in the preceding seven years that were finally determined against them or left pending at least two years without trial or hearing; (2) repeatedly relitigating, in propria persona, a matter already finally determined against them; (3) repeatedly filing unmeritorious motions or papers, conducting unnecessary discovery, or otherwise using frivolous or delay-only tactics while self-represented in a litigation; (4) having already been declared a vexatious litigant by any state or federal court in a matter based on the same or substantially similar facts; or (5) pursuing meritless litigation against a person protected by a domestic violence restraining order, while that order is in effect, that harasses or intimidates the protected person.
Every other section in this title depends on these definitions. A defendant moving under § 391.1, a court entering a prefiling order under § 391.7, or a litigant seeking to vacate one under § 391.8 all measure the case against the categories this section sets out.
Frequently Asked Questions
What makes someone a "vexatious litigant" under California law?
Section 391(b) lists five ways: repeated unsuccessful or stalled self-represented litigation over the past seven years, repeatedly relitigating a settled matter, repeatedly filing frivolous or delay-only papers while self-represented, a prior vexatious litigant declaration by another court on similar facts, or meritless litigation against a person protected by a domestic violence restraining order.
Does the five-litigations category only count cases I lost?
No. Section 391(b)(1) also counts litigation left pending, without being brought to trial or hearing, for at least two years when that delay was unjustified, not only cases finally decided against the person.
Does being a corporation or represented by counsel affect these definitions?
The propria persona categories in Section 391(b)(1) through (3) apply to self-represented litigation. "Defendant" under this section includes corporations, associations, partnerships, firms, and government entities, and "plaintiff" includes a self-represented attorney.
What is "security" under this title?
Section 391(c) defines it as an undertaking to assure payment of the defendant's reasonable expenses, including attorney's fees and expenses beyond ordinary taxable costs, incurred because of the vexatious litigant's litigation.
Amendment History
Amended by Stats 2022 ch 84 (AB 2391),s 1, eff. 1/1/2023. Amended by Stats. 1994, Ch. 587, Sec. 3.5. Effective January 1, 1995.
Source & verification. Section text is reproduced verbatim from
the Deering's California Codes Annotated / vLex. Enacted by the California Legislature.
Last verified July 28, 2026.
· Official source
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