Who this is for: Missouri adults who want to make sure their will is legally airtight. What it covers: What Missouri law actually requires for a valid will: signatures, witnesses, mental capacity, and what happens when requirements are not met. Why it matters: A will that misses even one of Missouri formal requirements can be thrown out entirely, leaving the estate governed by state intestacy laws. Patrick Nolan is an estate planning attorney at Nolan Law Firm in Kirksville, Missouri.
What Really Happens If You Don’t Get It Right
A will isn’t a feel-good formality. It’s a line in the concrete, proof of who gets what when you’re no longer around to say it yourself. Skip the legal steps and the State of Missouri, not you, calls the shots. Maybe your house goes to the cousin you never liked. Maybe your son gets nothing. That’s what intestate succession brings—order, but not yours. People who die without a clear, valid will leave family on edge, sometimes squabbling over the smallest things, sometimes tied up in court. Missouri accepts no substitutes for its formal requirements. Miss a step, and your will could be worthless.
Who Can Write a Will in Missouri?
You can’t just scribble a letter and call it a will if you’re too young. Missouri draws the line at 18, unless a judge says you’re emancipated or you’re serving in the armed forces—then you count as an exception. Legal adulthood counts here for a reason.
It takes more than the right birthday. You have to be of sound mind, too. That means you actually understand what you own, who those people around you are, and what your decisions will mean. Missouri courts will toss a will if you were confused or manipulated at signature time. Too many have tried to slide things by when someone’s memory fades. The court won’t play along.
What Missouri Law Requires—The Paper, the Signatures, the Witnesses
No oral agreements. No video diaries. Missouri wants it in ink. Section 474.320, RSMo, puts every step down in black and white:
- Written Document: Every word goes on paper. Oral (spoken) wills don’t count unless you’re in the military during wartime, and even that is rare.
- Testator’s Signature: You sign your own will. If you physically can’t, someone else can sign, but only right there in front of you and at your direction. No backroom signatures allowed.
- Witnesses: At least two people with nothing to gain—they’re not inheriting anything—must witness the whole thing. Missouri will let a beneficiary sign as a witness, but they risk losing their inheritance unless more safeguards come into play.
The Hard Reality About Witnesses in Missouri
One mistake ruins everything: the witnesses must see you sign, or you must state plainly that it’s your signature. Then, right in that moment, both witnesses sign too. Everyone should be able to look each other in the eye. It’s about certainty and cutting out fraud. No shortcuts, no proxy signings, no stories.
Self-Proving Wills—Why Not Skip the Back-and-Forth?
Probate moves faster if you nail down the details while you’re still here. Missouri lets you make a will “self-proving.” That means the court takes it as valid, up front, with no need to chase down witnesses again after you’re gone.
Here’s the move: the testator and both witnesses sign a sworn affidavit, in front of a notary, at the time the will is made. This paper says the will was signed, everyone acted freely, nobody seemed unwell or pressured. The notary’s stamp keeps it tight. Attach it to your will. Not mandatory, but it spares your family headaches and drama later.
Handwritten (Holographic) Wills—Don’t Lean on a Shortcut
Missouri isn’t like some other states. Writing a will in your own hand, start to finish, isn’t enough. Unless you use two qualified witnesses, any “holographic will” probably won’t hold up. The risk? Someone finds a letter or a diary and expects their claim to work. It usually won’t. Follow Missouri’s formal path or you’re only asking for trouble.
Who Counts as a Witness—And Who Doesn’t
There’s a trap here. The law doesn’t bar beneficiaries from serving as witnesses, but the price is steep. If a witness stands to get something, the gift can disappear—unless two extra, non-beneficiary witnesses sign off. That stops deals made in shadow or stories from changing after you’re gone. If you want zero doubts, pick witnesses with no stake in your estate.
How Do You Change or Cancel a Missouri Will?
Life throws curveballs. Divorces, new kids, burned bridges—they all change the game. Missouri lets you amend your will with a codicil (that’s a formal update, same witness and signature rules). No shortcuts for tweaks. Or you can just write a whole new will, with a clear instruction to cancel the old one.
There’s the scorched-earth option, too. Physically destroy the original—rip it up, burn it, obliterate it—with clear intent. Or sign a later writing or declaration, if it meets all the legal formality. Anything less leaves the door open for confusion.
Missouri courts want clarity: which document wins? That’s why half-measures backfire. Keep your estate plan squared away.
Common Mistakes—And Why Families Pay the Price
Missouri’s probate files are thick with badly made wills. Too few witnesses. Witnesses who stand to gain. Wills unsigned. Documents written when the testator was shaky or sick. Every shortfall invites court fights and delays. Sometimes, it voids the will entirely, sending everything into intestate chaos.
Don’t gamble. Talk to a Missouri estate lawyer. They’ll spot every required step and help you avoid the fallout.
Rapid-Fire Questions—The Details That Matter
Do You Need a Lawyer to Write a Will in Missouri?
The law says no. But if you fly solo, the odds of missing a key requirement go up—especially if you own a business, have kids from previous marriages, or hold complex assets. One mistake can undo your intentions. A lawyer stacks the deck in your favor.
What About Electronic Wills?
Missouri isn’t there yet. Electronic wills don’t count. You need a physical will, with ink signatures, and in-person witnesses. You can store a scanned or digital copy for your records, but the court wants the real, original paper.
Where Should You Keep the Will?
Put your will where it survives fire, flood, and nosy hands. A locked home safe or your lawyer’s office works. Some people use a bank safe deposit box, but access delays can frustrate families. Tell your executor or a trusted relative where to look—and maybe leave a sealed note with your lawyer in case something goes wrong.
Marriage, Divorce—Do They Change the Will?
Marriage doesn’t wipe the slate, but divorce almost always cuts your ex-spouse out, unless you wrote it otherwise. Life changes mean will changes. Update your will after every big family event so it matches your new reality.
Don’t Leave Your Future to Ambiguity
Missouri spells out the rules for a reason—to make sure what you want is what actually happens. These aren’t loose guidelines; they’re boundaries with weight. If you leave gaps, the law, courts, and sometimes strangers on the bench will step in and decide.
An up-to-date, correctly made will serves as your voice when you’re silent. If you’re unsure where to start, or just want to make sure nothing’s left unspoken, find a Missouri estate lawyer who knows these rules. It’s not just about assets—it’s about respect for the people left behind.
Frequently Asked Questions: Missouri Will Requirements
What makes a will legally valid in Missouri?
Under RSMo 474.320, a valid Missouri will must be in writing, signed by the testator (or by another person at the testator direction and in their presence), and witnessed by at least two competent adults who sign in the testator presence. The testator must be at least 18 years old and of sound mind at the time of signing.
What happens if a Missouri will is found invalid?
If a Missouri will is found invalid due to missing signatures, improper witnessing, lack of testamentary capacity, or undue influence, the court treats the decedent as having died intestate. RSMo 474.010 then controls who inherits, which may bear no resemblance to what the decedent actually wanted.
Can a beneficiary be a witness to a Missouri will?
Missouri law does not automatically invalidate a will if a beneficiary serves as a witness, but under RSMo 474.330 a beneficiary-witness can take only as much as they would have received under intestate succession. To avoid any complications, use two disinterested witnesses who inherit nothing under the will.
Does Missouri recognize handwritten wills without witnesses?
No. Missouri does not recognize unwitnessed holographic wills for most people. A handwritten will must still be signed by the testator and witnessed by two competent adults, the same requirements as a typed will. Some states waive witnessing for fully handwritten wills; Missouri does not.
What is testamentary capacity under Missouri law?
Testamentary capacity in Missouri requires the testator at signing to understand the nature and extent of their property, their family and natural heirs, the nature of making a will, and how these elements form a coherent plan. Mental illness or dementia does not automatically negate capacity. The court looks at mental state at the moment of signing.
How long does probate take in Missouri?
Probate in Missouri typically takes 6 to 12 months for an uncomplicated estate. The process includes filing the will with the Probate Division, notifying creditors and heirs, inventorying assets, paying debts and taxes, and distributing assets. The small estate affidavit for estates under 40,000 dollars can bypass formal probate entirely.
