What Voids a Will?

Key Takeaways

• Missouri law requires a valid will to be written, signed, and witnessed by at least two people.
• A will may be voided by improper execution, fraud, forgery, or a testator lacking mental capacity.
• Undue influence, coercion, or manipulation can render a will legally invalid in Missouri courts.
• Missouri law allows revocation through a subsequent written will or physical destruction of the document.
• When a will is declared invalid after death, Missouri intestacy laws govern how assets are distributed.

TdD Attorneys at Law LLC helps families and individuals in St. Louis, Missouri, protect the wishes of their loved ones. A will can be voided in three broad ways: a deliberate physical act by the person who made it, the execution of a newer will, or a legal challenge proving a defect in how the will was drafted, signed, or witnessed. What voids a will is rarely obvious, and the consequences of a flawed document often do not surface until after the person who wrote it has passed.

What Makes a Will Legally Invalid?

Not every document labeled a “will” holds up in a Missouri probate court. If the document fails to meet Missouri’s legal requirements, a court may refuse to admit it to probate entirely.

A Will Must Meet Specific Legal Requirements

Under RSMo § 474.310, only a person of sound mind who is at least 18 years old, or an emancipated minor, may execute a valid will in Missouri. Beyond age and mental capacity, the document itself must satisfy the formal execution requirements established in RSMo § 474.320: the will must be in writing, signed by the person making it (called the testator), and confirmed by at least two witnesses who sign the document while the testator is present.

Common Reasons a Will May Be Declared Void

A will can be challenged on several grounds, ranging from technical mistakes at signing to deliberate wrongdoing or questions about the testator’s mental state.

• Improper execution: Occurs when the required steps for signing or witnessing are not properly completed.
• Fraud: Arises when someone deceives the testator into signing a document under pretenses. A signature obtained through deception does not reflect genuine consent.
• Forgery: Involves a signature or document that was fabricated without the testator’s knowledge or participation.
• Revocation: Is worth noting separately: a testator can intentionally void their own will through steps Missouri law expressly recognizes.
• Lack of mental capacity: If the testator did not understand what they were signing, what property they owned, or who their natural heirs were, a court may rule the will invalid for lack of capacity.

How Undue Influence and Lack of Capacity May Affect a Will

Undue influence occurs when another person exerts pressure, manipulation, or coercion over a testator to such a degree that the resulting will reflects that person’s wishes rather than the testator’s own. It most often surfaces in cases involving elderly or seriously ill individuals dependent on a caregiver or family member. Courts look for signs that the testator was cut off from family or other advisors and that the will’s terms simply do not add up any other way.

Cognitive decline can independently void a will. A testator experiencing dementia, severe depression, or another condition that impairs judgment may lack the mental capacity the law requires under RSMo § 474.310, and capacity is evaluated as of the moment the will was signed, making the factual record around that date critically important.

Can a Will Be Revoked or Replaced?

Missouri law gives a person several ways to change or cancel a will they have already signed, with RSMo § 474.400 identifying the recognized methods of revocation.

A newer will automatically supersedes an earlier one when it either expressly revokes the prior document or is so different in its terms that the two documents cannot reasonably coexist.

Physical destruction is another recognized method. Burning, tearing, canceling, or otherwise obliterating the document by the testator, or by someone acting at the testator’s direction, constitutes a valid act of revocation under Missouri law.

What Happens if a Will Is Found to Be Invalid After Death?

When a court invalidates a will after the testator has passed, Missouri’s intestacy laws determine how assets pass among surviving relatives, following a fixed priority order based on family relationship.

If a prior valid will exists, that document may be admitted to probate instead, but without one, the result may bear little resemblance to what the deceased actually wanted.

Understanding Your Rights in a Will Dispute

Questions about what voids a will in Missouri rarely have simple answers. Whether you are concerned about the validity of an existing document or believe a loved one’s will was the product of fraud or undue influence, acting quickly matters. TdD Attorneys at Law LLC represents clients across St. Louis in estate litigation and will contests. Call (314) 276-1318 today to schedule a consultation.