Missouri Anti-SLAPP Law (UPEPA) Takes Effect, Replaces 2004 Statute

Missouri Anti-SLAPP Law Changes Today: RSMo 537.528 Repealed, UPEPA Takes Effect

Missouri's narrow 2004 anti-SLAPP statute, RSMo 537.528, was repealed today, August 28, 2026. In its place, RSMo 537.529, Missouri's version of the Uniform Public Expression Protection Act, now covers most civil lawsuits based on protected speech, not just quasi-judicial hearings.

Information last verified on August 28, 2026.

Jurisdiction: This article covers Missouri state law only. RSMo 537.529 governs civil actions filed in Missouri state courts on or after August 28, 2026. It does not change federal law, court rules in other states, or any claim filed before that date.

What Happened

Effective today, Missouri repealed RSMo 537.528 and enacted RSMo 537.529 in its place. Both changes trace to the same effective date because they were carried in the same 2026 legislation: Senate Bill 1067, plus the merged Senate Bills 835 and 1111, which the Missouri Revisor of Statutes' source note lists together as the origin of the new section. Article III, section 29 of the Missouri Constitution provides that no law passed by the general assembly, other than an appropriation act, takes effect until ninety days after the session adjourns, absent an emergency clause adopted by a two-thirds vote. That ninety-day rule is why bills from a regular session ordinarily land on the statute books on August 28 rather than on the day they are signed.

The Missouri Revisor of Statutes' page for the old section now reads only that RSMo 537.528 is repealed, with a version history showing it ran from August 28, 2004 to August 28, 2012, then in amended form from August 28, 2012 until its repeal today. The new section, RSMo 537.529, carries the formal heading "Uniform Public Expression Protection Act," and subsection 1 states the section may be cited by that name.

The old statute reached a narrow slice of cases: a special motion was available only against a lawsuit targeting conduct or speech connected to a public hearing or public meeting in a quasi-judicial proceeding before a governmental tribunal or decision-making body, think testimony before a city council, planning commission, or zoning board. Most ordinary defamation, invasion of privacy, or interference claims arising from online posts, news coverage, or consumer reviews fell outside it entirely. Readers can see how that gap plays out under Missouri's separate defamation statute on the site's Missouri defamation laws page, and how the same UPEPA text has been applied elsewhere in a New Jersey court's decision that a law firm's blog post was protected speech.

The Missouri Senate's bill-tracking page lists SB 1067's current status as signed by the governor, with an effective date of August 28, 2026. That page does not display the date the governor signed the bill, so this article does not state one.

What the Law Actually Says

Scope. RSMo 537.529 subsection 3 applies the special motion to a cause of action based on a person's communication in a legislative, executive, judicial, administrative, or other governmental proceeding; a communication on an issue under consideration or review in such a proceeding; or the exercise of the right of freedom of speech or of the press, the right to assemble or petition, or the right of association, guaranteed by the United States Constitution or the Missouri Constitution, on a matter of public concern. That third category is the one the old law lacked, and it is broad enough to reach most defamation, tortious interference, and similar claims arising from public commentary, reporting, or online reviews.

Exclusions. Subsection 4 carves out three categories: claims against a governmental unit or its employee or agent acting in an official capacity; claims brought by a governmental unit or its employee or agent to enforce a law protecting against an imminent threat to public health or safety; and claims against a person primarily engaged in selling or leasing goods or services, where the claim arises from a communication tied to that sale or lease. The subsection adds that this last, commercial exclusion does not reach dramatic, literary, musical, political, journalistic, or artistic work, so a media outlet or reviewer is not swept out of protection merely because the outlet is a business.

Mechanics. A defendant has 60 days after being served with the pleading to file the special motion to dismiss, or later on a showing of good cause, per subsection 5. Filing the motion stays the case, including discovery and any pending hearing or motion between the moving and responding party, under subsection 6; limited discovery is allowed only if a party shows specific information is necessary to decide the motion and is not otherwise available. A fees motion under subsection 12 is not stayed. The court must hear the motion within 60 days of filing (subsection 7) and rule within 60 days of the hearing (subsection 10), looking at the pleadings, the motion, any replies, and evidence of the kind considered on summary judgment (subsection 8).

Dismissal standard. Under subsection 9, the court dismisses with prejudice if the movant shows the statute applies, the responding party fails to establish an exclusion, and either the responding party cannot make a prima facie case on each essential element of the claim, or the movant shows the claim fails as a matter of law with no genuine factual dispute. A voluntary dismissal without prejudice by the plaintiff does not defeat the movant's right to a ruling or to fees; a voluntary dismissal with prejudice establishes that the movant prevailed for fee purposes.

Appeal and fees. A moving party may appeal an order denying the motion, in whole or in part, within 21 days as a matter of right under subsection 11, and that appeal stays proceedings between all parties until it concludes. Subsection 12 makes a fee award mandatory for a prevailing movant, and available to a prevailing responding party only if the court finds the motion was frivolous or filed solely to delay.

Effective date. Subsection 15 limits the new law to a civil action filed, or a cause of action asserted in a civil action, on or after August 28, 2026. Cases already pending before that date continue under the old rules, or without any special-motion procedure at all if they fall outside RSMo 537.528's narrower reach.

How This Affects You

Anyone sued in Missouri state court on or after today over speech connected to a governmental proceeding or a matter of public concern now has access to a special motion that did not exist for most speech claims before today. That includes reporters, bloggers, reviewers, and ordinary commenters, subject to the exclusions above. The motion is not automatic protection, it requires meeting the statute's tests within tight deadlines, and it comes with real downside: a party who loses can be ordered to pay the other side's fees.

Anyone considering filing a defamation, privacy, or interference claim in Missouri based on the other party's speech should expect the case to be screened early, and should weigh whether the claim can clear the prima facie and legal-sufficiency bars in subsection 9 before filing, since a case that cannot may end in a mandatory fee award against the plaintiff. None of this changes the underlying substantive law of defamation or privacy in Missouri, covered on the site's broader defamation laws by state hub; RSMo 537.529 is a procedural screening tool layered on top of those existing claims, not a new cause of action or a new defense on the merits.

Analysis: Why This Matters

The following is analysis from the Recording Law Editorial Team.

The practical significance of this change is the scope expansion, not the existence of an anti-SLAPP statute itself. Missouri has had some form of special motion since 2004, but RSMo 537.528's quasi-judicial-hearing trigger meant it rarely reached the fact pattern that drives most modern speech litigation: a news story, a blog post, an online review, or a social media post that a subject dislikes and sues over. RSMo 537.529's third category, the exercise of constitutional speech, press, assembly, petition, or association rights on a matter of public concern, is what closes that gap.

Missouri joins a growing number of states that have adopted the Uniform Law Commission's model UPEPA text rather than writing a bespoke anti-SLAPP statute from scratch. That matters procedurally: subsection 14 of the Missouri statute directs courts to give consideration to promoting uniformity among the states that have enacted the uniform act, which invites Missouri courts to look at how sibling states, including South Dakota's newer statute covered in the site's reporting on South Dakota's first anti-SLAPP law, have construed the same or similar text. A shared statutory text does not guarantee identical outcomes across states, since courts still apply it to different facts and within different procedural traditions, but it does mean Missouri is not writing on a blank slate.

The tight timeline mechanics, a 60-day filing window, a 60-day hearing deadline, and a 60-day ruling deadline, are themselves a policy choice: they are designed to resolve the threshold question before a defendant absorbs the cost of full discovery and trial preparation, which is the core economic harm a SLAPP suit is meant to inflict regardless of its ultimate merits. The mandatory fee-shifting in subsection 12 reinforces that design by making a losing movant's exposure symmetrical with a losing respondent's exposure to costs, though the statute sets a materially higher bar, a finding of frivolousness or delay, before a losing movant pays the responding party's fees.

This article is provided for general informational purposes only and does not constitute legal advice. Anyone facing a lawsuit, or considering filing one, that may be affected by RSMo 537.529 should consult a licensed Missouri attorney about their specific circumstances.

Related articles

• Missouri Defamation Laws: Libel and Slander
• Defamation Laws by State
• South Dakota's First Anti-SLAPP Law, SB 137
• New Jersey Court: Anti-SLAPP Law Shields a Law Firm's Blog Post

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Last updated: 2026-08-28. This is a developing story; details verified as of 2026-08-28.

Frequently Asked Questions

What is Missouri's new anti-SLAPP law called?

It is RSMo 537.529, and subsection 1 says it may be cited as the Uniform Public Expression Protection Act, often abbreviated UPEPA. It took effect August 28, 2026.

When did the new Missouri anti-SLAPP law take effect?

August 28, 2026. Subsection 15 limits the law to a civil action filed, or a cause of action asserted in a civil action, on or after that date.

What happened to Missouri's old anti-SLAPP statute?

RSMo 537.528, in effect since 2004, was repealed on August 28, 2026, the same day RSMo 537.529 took effect.

What kinds of claims does the new law cover?

Under subsection 3, it covers a civil claim based on a person's communication in a governmental proceeding, a communication on an issue before such a proceeding, or the exercise of free speech, press, assembly, petition, or association rights on a matter of public concern.

What claims are excluded from Missouri's UPEPA?

Subsection 4 excludes claims against a governmental unit or its official acting in that capacity, government enforcement actions to protect against an imminent public health or safety threat, and most claims against a business over its own sale or lease communications, though that business exclusion does not cover dramatic, literary, musical, political, journalistic, or artistic work.

How long does a defendant have to file the special motion to dismiss?

No later than 60 days after being served with the pleading asserting the claim, under subsection 5, unless the court allows a later filing for good cause.

Does filing the motion pause the rest of the lawsuit?

Yes. Subsection 6 stays discovery and other proceedings between the moving and responding party once the motion is filed, and the stay continues through any appeal of the ruling.

Can a party appeal if the motion is denied?

Yes. Subsection 11 allows the moving party to appeal an order denying the motion, in whole or in part, within 21 days as a matter of right.

Who pays attorney's fees under the new law?

Subsection 12 requires the court to award costs and reasonable attorney's fees to a moving party who prevails on the motion, and to a responding party only if that party prevails and the court finds the motion was frivolous or filed solely to delay the case.