Contest a Will in California: What Is the Success Rate for Contesting a Will – and Can You Contest a Will and Win?

To contest a will in California is to ask the probate court to decide that a last will and testament is invalid in whole or in part. A will contest is a lawsuit within the probate case, and contesting a will involves following specific procedures under California probate law.

Under California Probate Code § 8250, when a will is contested, the person contesting files an objection to probate of the will, and the court issues a summons that must be served on the people who would be affected by the outcome. That objection is how you formally file a will contest and state your reasons to contest.

For a will to be valid under California law, it usually must meet the requirements of Probate Code § 6110: the will must be in writing, signed by the testator (or someone signing in the testator’s presence and at their direction), and generally witnessed by at least two witnesses.

In most cases, the probate process begins when someone files a petition for probate, asking the court to admit the will to probate and appoint an executor. Once probate is opened and the will is admitted to probate, strict deadlines for contesting a will in California begin to run, which is why early legal advice is so important.

Not everyone who is upset by a will has the right to contest it. California probate law limits contests in California to people with legal standing, often called interested parties. Legal standing means you have a direct financial stake in the estate.

People who may contest a will in California typically include:

• A beneficiary named in the last will and testament
• A beneficiary named in a prior will who would benefit if the current will is invalid
• An heir at law who would inherit under intestacy laws if there were no valid will
• Sometimes a creditor or other person with a clear financial interest in the estate

Your right to contest depends on whether the outcome of the probate and estate distribution would change if the will is declared invalid. If you receive a larger inheritance, or any inheritance under intestacy laws or a prior estate plan, you probably have standing to contest. If you would get nothing no matter what happens, you likely do not.

For example, if a parent’s will suddenly leaves everything to a non-relative and cuts out the children, each child is an heir and an obvious interested party. On the other hand, a family friend who was never a beneficiary and has no legal claim under intestacy laws would not have standing to contest a will and win.

At OC Trusts Lawyer, one of the first steps is to confirm legal standing. That means reviewing the will, any prior trust or estate plan, and the family tree to determine whether you can even file a petition before spending time and money on litigation.

Having standing is not enough. You also need valid grounds to contest the will. California Probate Code and California law recognize several specific grounds for contesting, and the court will not set aside a will just because it feels unfair.

Common legal grounds to contest include:

Lack of mental capacity focuses on whether the testator had sufficient mental capacity to understand the nature of making a will, the nature of their property, and their relatives or other likely beneficiaries. The statute explains that a person is not mentally competent to make a will if they cannot understand these basic things. Evidence of dementia, hallucinations, or severe cognitive decline can support this ground to contest.

Undue influence arises when someone uses pressure, manipulation, or control over a vulnerable testator. California law describes factors indicative of undue influence, such as vulnerability, the apparent authority of the influencer, and actions or tactics used.  These cases often involve caregivers, new partners, or a single child who isolates the decedent and benefits from a surprise change in the estate plan.

Improper execution is another frequent reason to contest a will in California. If the will was not signed, witnessed, or drafted in the manner required by the statute, the court may find it invalid. The contestant must gather evidence to prove those defects, such as missing witnesses or contradictory testimony about the signing.

A strong contest will in California usually use one or more of these legal grounds for contesting, backed by records, witness statements, and expert opinions rather than speculation.

Yes. A beneficiary in California has the legal right to sue the trustee for breach of fiduciary duty, including self-dealing, mismanagement of trust assets, or other breaches. Beneficiaries may file a petition in probate court seeking court intervention.

California law provides multiple avenues for legal action, including compelling an accounting, recovering trust assets, or requesting the removal of a trustee. Beneficiaries are entitled to information about the trust under California Probate Code §§ 16060–16063, which requires trustees to keep beneficiaries reasonably informed.

Early engagement of an experienced trust litigation attorney can help protect the trust’s value and prevent further misconduct.

Even a strong contest case can be lost if you miss the deadline. The statute of limitations for revoking probate is found in California Probate Code § 8270.

It states that within 120 days after a will is admitted to probate, any interested person (with certain exceptions) may petition the court to revoke the probate of the will, and that petition must include objections setting forth written grounds of opposition. 

In plain terms:

• After the will is admitted to probate, you generally have 120 days from the date of that order to file a petition asking the court to revoke its order and contest the will.
• The petition must state your legal grounds upon which you seek to invalidate the will.
• If you wait longer than 120 days from the date the order is entered, you may lose your right to contest, even if your grounds are strong.
• There are limited exceptions for minors and people who were legally incompetent with no guardian when the will was admitted to probate, but most adults must act within 120 days from admission. 
• Because of these strict deadlines, anyone who wants to contest a will and win should speak with an experienced probate attorney as soon as they learn a will has been filed.

Clients understandably want to know the success rate for contesting a will. Unfortunately, there is no official statewide statistic telling you the exact success rate of contesting a will or the exact chances of success in every case. Every contest case is different, and the outcome of a will contest depends on the specific facts and evidence.

Some general realities about the success rate of contesting a will:

• Many will contests settle before trial, with beneficiaries renegotiating how the inheritance is divided.
• Weak contests brought without solid evidence supporting your claim tend to fail and can be expensive.
• Strong contests, where clear undue influence, lack of capacity, or fraud is supported by medical records, testimony, and documents, can succeed.

Your likelihood of success depends on:

• The legal grounds for contesting you rely on and how strong they are
• Whether you can gather evidence to prove those grounds
• The impact of any no-contest clause
• The size of the estate and the other parties’ willingness to negotiate
• The experience of your contest attorney and the probate litigation lawyers involved

Instead of asking only what the success rate is, a better question is: given my facts, what are my chances of successfully contesting this particular will? OC Trusts Lawyer focuses on case-specific analysis so you can decide whether it is worth contesting before you commit to full litigation.

Because contesting a will involves asking the court to overturn a formal document, evidence is critical. The court will typically not act based on suspicion alone. Evidence is required to support the legal grounds on which you assert.

Examples of evidence supporting your claim include:

• Medical records showing cognitive decline, dementia, or other conditions affecting the testator’s mental capacity around the time the will was signed
• Testimony from friends, family members, caregivers, and professionals who observed the testator and can speak to capacity or undue influence
• Emails, texts, letters, and social media showing pressure, isolation, or misrepresentations by someone who benefits from the will
• Earlier wills, living trust documents, and other estate plan records that reveal a sudden and unexplained change in beneficiaries
• Financial account statements and property records showing transfers that align with undue influence or fraud

To successfully contest a will and win, your experienced probate litigation attorney will usually need to gather evidence quickly, use discovery tools in probate court, and, in some cases, work with experts such as geriatric psychiatrists to interpret medical records. The more organized your evidence is, the stronger your contest process becomes.

Because evidence is required and the legal process can be complicated, taking legal action without an experienced probate attorney can harm your chances of success.

Even when you can contest and have legal grounds, you still need to decide whether it is worth contesting. This is a practical question that depends on both the law and your goals.

Key factors include:

• Size of the estate and the inheritance at stake
• Strength of the legal grounds for contesting and the evidence supporting your claim
• Emotional and financial costs of litigation
• The presence of a no-contest clause and the potential consequences if you lose
• Whether settlement, mediation, or modifying a related trust is possible

Sometimes, the best strategy is to pursue full trust litigation or probate litigation and ask the court to revoke the order admitting the will, invalidate the document, and have intestacy laws or a prior will apply. Other times, targeted objections, mediation, or negotiation among beneficiaries can protect your interests without a long trial.

Talking these issues through with an experienced probate attorney or estate planning attorney who understands probate law and the probate process can help you decide whether taking legal action is likely to improve your outcome.

1. Can I contest a will simply because I was disinherited?

No. California courts will not invalidate a will simply because you received less than expected. You must have legal standing and valid legal grounds, such as undue influence, fraud, or lack of mental capacity.

2. How long do I have to contest a will in California?

In most cases, California Probate Code § 8270 gives interested parties 120 days after the will is admitted to probate to file a contest. Missing the deadline can permanently bar your claim.

3. Who has the legal right to contest a will?

Generally, heirs, beneficiaries under the current will, beneficiaries under a prior will, and others with a direct financial interest in the estate may have standing to contest a will.

4. What is the most common reason wills are successfully challenged?

Undue influence is one of the most common grounds for a successful will contest, particularly when a vulnerable person was pressured into changing their estate plan.

5. What evidence is needed to contest a will?

Common evidence includes medical records, witness testimony, emails, text messages, prior estate planning documents, and financial records that support the claim being made.

6. Can a person with dementia legally sign a will?

Possibly. A diagnosis of dementia alone does not automatically invalidate a will. The key question is whether the person had the required testamentary capacity when the will was signed.

7. What happens if the court finds the will invalid?

The court may enforce a prior valid will or distribute the estate according to California intestacy laws if no valid will exists.

8. Are will contests usually settled before trial?

Many will contests resolve through settlement negotiations or mediation before reaching a probate trial, especially when both sides face litigation risks.

9. Can a no-contest clause prevent me from challenging a will?

Not always. California law limits the enforcement of no-contest clauses, but they can still create risks depending on the facts and the grounds asserted.

10. Is hiring a probate litigation attorney important in a will contest?

Yes. Will contests involve strict deadlines, complex procedural rules, and substantial evidence requirements. An experienced probate litigation attorney can evaluate the case and protect your rights throughout the process.

Contesting a will is a serious legal matter that directly affects your inheritance and your family’s future. It is also technical: you must file a petition or objection on time, state precise legal grounds, and gather evidence. 

OC Trusts Lawyer focuses on California trust and estate disputes, including will contests and trust litigation. Suppose you want to contest a will in California, or you are considering contesting and want to understand your chances of success. In that case, OC Trusts Lawyer can help you gather evidence, understand the legal grounds for contesting, and pursue an outcome that respects both the law and your loved one’s true intentions.