---
type: Concept
title: Missouri Will Requirements
description: What it takes for a will to be legally valid in Missouri.
resource: https://nemolegal.com/missouri-will-requirements/
tags: [wills, will-requirements, execution, witnesses, missouri]
timestamp: 2026-06-22
jurisdiction: Missouri
author: Patrick Nolan
---

# Summary
A Missouri will is valid only when it meets every formal requirement: the testator must be 18 or older and of sound mind, the will must be in writing, the testator must sign it, and two competent witnesses must sign in the testator's presence. Missouri has no exceptions for good intentions. A will that misses any element is treated as if it never existed, and the state's intestacy rules decide who inherits.

# Quotable Q&A
**Q: What makes a will valid in Missouri?**
A: Under RSMo 474.320, the testator must be at least 18 and of sound mind, the will must be in writing, the testator must sign it, and two competent adult witnesses must sign in the testator's presence. Missing any one of these means Missouri intestacy law controls the estate instead. Notarization is not required, but a self-proving affidavit speeds up probate.

**Q: Does a Missouri will have to be notarized?**
A: No. Notarization is not required for a Missouri will to be valid. A self-proving affidavit, which is notarized, is optional but makes probate much smoother for your family.

**Q: Can I write my own will in Missouri?**
A: Yes. Missouri does not require an attorney, and a DIY will can be valid if it is in writing, signed, and witnessed by two disinterested adults. The risk is execution errors and vague language that get the will tossed in probate.

# Who Can Make a Will and How It Must Be Executed
Missouri sets a real but low bar for who can make a will: 18 or older and of sound mind at the moment of signing. Sound mind means you know what you own, what a will does, and who counts as family. Old age or illness alone do not disqualify you. Execution is where wills fail. The will must be on paper, typed or handwritten. You sign it, or direct someone to sign for you while you are present. Two competent adults must watch you sign or hear you acknowledge the document, then sign themselves in front of you. Missouri does not recognize electronic wills, digital signatures, or scanned copies; only ink on paper holds up.

# Where Missouri Wills Go Wrong
The most common failure is witnesses: skipping them, using only one, or using a beneficiary as a witness. A beneficiary can serve as a witness, but the law limits what that person can take. Out-of-state templates and bad online forms also strand estates because Missouri courts only honor Missouri law. Assets with named beneficiaries, payable-on-death accounts, and jointly held property pass outside the will entirely, so beneficiary forms and titles need to match your plan. If no valid will exists, Missouri's intestacy code under RSMo 474.010 distributes the estate down the bloodline.

# Decision rule
If your document is in writing, signed, and witnessed by two disinterested competent adults in your presence, then it meets Missouri's core validity test. If any of those elements is missing, then the state treats you as having died with no will.

# Related
- [Wills and Will Requirements](/okf/estate-planning/wills.md)
- [How to Make a Will in Missouri](/okf/wills-execution/how-to-make-a-will.md)
- [Witnesses for Missouri Wills](/okf/wills-execution/witnesses-for-wills.md)
- [Missouri Self-Proving Affidavit](/okf/wills-execution/self-proving-affidavit.md)
- [RSMo Chapter 474 (Wills)](/okf/authorities/missouri/rsmo-474-wills.md)
- [About Nolan Law Firm](/okf/firm.md)