By Lori Ashmore-Peters, Managing Attorney, The Ashmore Law Firm, P.C. Updated October 2026.
What are 7 ways a will can be invalid in Texas?
A Texas will can be found invalid because of improper execution, lack of mental capacity, undue influence, fraud or forgery, revocation, or because the testator was under 18 and not married or in the armed forces. A surprising distribution, such as disinheriting a child, does not invalidate a will by itself, but it often prompts a closer look for these problems.
Are you questioning whether a loved one's Last Will and Testament is valid? Texas courts start from the assumption that a properly signed will is valid, so the person challenging it carries the burden of proof. Here are seven ways a will can be found invalid, and what it takes to prove each one.
1. Improper execution
This is one of the most common reasons a will fails. In Texas, a typical will must be in writing, signed by the person making it (the testator), and signed by two credible witnesses over the age of 14 in the testator's presence. A will written entirely in the testator's own handwriting can be valid without witnesses. If these formalities were not followed, the will may not be admitted to probate. A self-proving affidavit, signed before a notary, makes a will much harder to challenge on these grounds.
2. Lack of mental capacity (testamentary capacity)
According to the Alzheimer's Association's 2025 report, an estimated 7.2 million Americans age 65 and older are living with Alzheimer's dementia, including about 459,000 Texans. Millions more have other forms of dementia or conditions that affect memory and judgment. Illness, medication, alcohol and drugs can also affect capacity.
To make a valid will, your loved one must have had sound mind at the time it was signed. That means he or she:
- Understood he or she was making a will and its effect;
- Knew the general nature and extent of his or her property;
- Knew his or her family and the people who would naturally expect to inherit; and
- Could hold these facts in mind long enough to make a reasonable decision about them.
What matters is capacity on the day the will was signed. A diagnosis alone does not prove a lack of capacity, and a person with dementia may still have lucid periods. Proving incapacity usually takes medical records, witness testimony and sometimes expert opinions, so speak with an experienced probate lawyer early.
3. Undue influence
This is one of the most heartbreaking reasons a will may be invalid. Undue influence means the will reflects someone else's wishes rather than the testator's own judgment. It is usually exercised by someone close to the testator, through pressure, isolation, intimidation or dependence. In Rothermel v. Duncan, 369 S.W.2d 917 (Tex. 1963), the Texas Supreme Court set out what must be shown:
- An influence existed;
- The influence was exerted in a way that subverted or overpowered the testator's mind when the will was signed; and
- The testator would not have signed the will but for that influence.
All three elements must be proven. Simply having the opportunity to influence someone is not enough.
4. Fraud or forgery
Fraud in the inducement means someone intentionally lied to the testator to change how he or she left property. For example, someone may tell a parent that a sibling was stealing from them or no longer needs an inheritance. An honest mistake is not fraud; the misrepresentation must be intentional. Forgery means the testator's signature, or part of the will, was faked. Both are difficult to prove and often require handwriting experts, documents and witnesses.
5. The will was revoked
A will can be revoked by a later will or codicil, or by the testator intentionally destroying or canceling it. If a newer valid will exists, it generally controls. In Texas, a divorce also generally revokes provisions in a will that benefit the former spouse.
6. The testator was under 18
In Texas, a person must be at least 18 years old to make a will, unless he or she is or has been married or is serving in the armed forces.
7. Surprising distributions invite scrutiny
An "unnatural distribution" (courts often say "unnatural disposition") is a will that leaves property differently than people would normally expect, given the testator's family. Common examples are leaving a child out entirely, dividing an estate very unequally among children, or leaving most of the estate to a caregiver, new friend or advisor instead of close family. In Texas, courts treat an unnatural disposition as one factor to weigh in a capacity or undue-influence claim, not as a reason to throw out a will on its own.
A will that leaves out a child or favors one person over the rest of the family is not invalid for that reason alone. Texas law allows you to leave your property as you choose, with some protections for a surviving spouse. But a surprising distribution often prompts relatives to look closely for capacity or undue-influence problems. When the decision is clearly stated in the will and explained to the family in advance, it is far harder to challenge. Read more in Disinheriting a Relative in Texas: Should You Tell Them First?
Don't wait: the two-year deadline
In Texas, a will contest generally must be filed within two years after the will is admitted to probate. Claims based on forgery or fraud may allow two years from when it was discovered. Waiting can cost you the right to challenge the will at all.
Frequently asked questions about Texas Wills
What makes a will invalid in Texas?
A Texas will can be found invalid if it was not properly signed and witnessed, the testator lacked mental capacity, it was the product of undue influence, fraud or forgery, it was later revoked, or the testator was under 18 and not married or in the armed forces.
What are the signing requirements for a will in Texas?
A typical Texas will must be in writing, signed by the testator, and signed by two credible witnesses over age 14 in the testator's presence. A will written entirely in the testator's own handwriting can be valid without witnesses. A self-proving affidavit makes it harder to challenge.
What is testamentary capacity in Texas?
Testamentary capacity means that when the will was signed, the testator understood he or she was making a will, knew the general nature of his or her property, knew his or her family members, and could hold those facts in mind long enough to make a reasonable decision.
Does a dementia diagnosis automatically make a will invalid?
No. What matters is the testator's mental capacity on the day the will was signed. A person with dementia may still have lucid periods. Proving incapacity usually requires medical records, witness testimony and sometimes expert opinions.
How do you prove undue influence in Texas?
Under Rothermel v. Duncan (Tex. 1963), a contestant must show that an influence existed, that it subverted or overpowered the testator's mind when the will was signed, and that the testator would not have signed the will without it. All three must be proven.
What is an unnatural distribution in a will?
An unnatural distribution, or unnatural disposition, is a will that leaves property differently than would normally be expected, such as disinheriting a child or leaving most of an estate to a caregiver instead of family. In Texas, it is one factor courts weigh in capacity or undue-influence claims, not a ground to invalidate a will on its own.
Can I contest a will because I was left out?
Not on that basis alone. Texas lets people leave their property as they choose, with some protections for a surviving spouse. Being disinherited may support a contest only if it points to a real problem, such as lack of capacity or undue influence.
How long do I have to contest a will in Texas?
Generally, a will contest must be filed within two years after the will is admitted to probate. Claims based on forgery or fraud may allow two years from when the forgery or fraud was discovered.
Does divorce revoke a will in Texas?
A divorce generally revokes provisions in a will that benefit the former spouse, but the rest of the will can remain in effect. A will can also be revoked by a later will or by the testator intentionally destroying it.
Do You Need to Contest a Will in the Dallas Area?
If you need to contest a will you should speak to an experienced lawyer as soon as possible. please contact us online or call our Dallas office directly at 214.559.7202. We help clients throughout the Dallas area with all of their legal needs and look forward to helping you.
