Can Siblings Contest a Will?

Written by Tanya Waterworth, Digital Content Writer

About Our Legal Expert: This content is produced with oversight by Michael Jefferies, Managing Director who has over 30 years’ legal experience.

A Guide to Sibling Disputes, Legal Grounds & What To Do Next

When a loved one dies, emotions run high and disagreements between siblings can surface quickly, but can siblings contest a will?  The short answer is yes; siblings can challenge a will in England and Wales – but only on specific legal grounds. It’s common for siblings to feel a will is ‘unfair’ but in order to contest a will, legal justification is required.

Disputes between brothers and sisters often involve complex family history, suspicions of undue influence, or sudden changes to a will that benefit one sibling over another. Simply feeling overlooked is not enough – evidence is essential.

If you believe your parent’s will does not reflect their true wishes, we work with specialist contentious probate solicitors. However, if your situation involves estrangement rather than sibling conflict, see our guide: Can Estranged Children Challenge a Will?

When Can Siblings Legally Dispute a Will in England & Wales?

Siblings may be able to contest a will if they can show that:

• The will is legally invalid,
• One sibling manipulated or influenced the deceased,
• The will was changed suddenly or suspiciously, or
• They are entitled to reasonable financial provision under the Inheritance Act 1975.

Sibling disputes often arise when:

• One sibling received a significantly larger share,
• A previously close sibling is suddenly cut out,
• A new partner or step‑sibling is favoured,
• One sibling was caring for the parent and had more influence,
• A sibling acting as attorney or carer who controlled access to the parent.

Strict time limits apply, especially for Inheritance Act claims, which must usually be issued within six months of probate.

Sibling‑Specific Grounds for Contesting a Will

Below are the most common legal grounds, explained through the lens of sibling disputes.

1. Lack of Testamentary Capacity

A will may be invalid if the parent did not understand:

• What they were signing,
• The extent of their estate, or
• How their decisions affected their children.

Sibling disputes often involve:

• A parent with dementia or cognitive decline,
• A parent who relied heavily on one sibling for care,
• A parent who made a new will during illness or hospitalisation.

Evidence may include medical records, GP notes, or statements from family members.

2. Undue Influence – Often a Key Issue Between Siblings

Sibling disputes frequently centre on allegations that one brother or sister:

• Pressured the parent,
• Restricted access to them,
• Controlled finances or communication,
• Encouraged sudden changes to the will,
• Became overly involved in the drafting process.

Courts require strong evidence — but patterns of behaviour, witness accounts, and solicitor notes can be powerful.

3. Lack of Proper Execution

A will may be invalid if it was not signed or witnessed correctly. Sibling‑specific issues include:

• A sibling acting as a witness (which can invalidate gifts),
• A rushed signing arranged by one sibling,
• Missing or unreliable witnesses.

4. Fraud or Forgery

Fraud is rare but does occur, particularly in high‑conflict sibling situations. Examples include:

• A forged signature,
• Pages swapped after signing,
• Misleading the parent about what they were signing,
• A sibling intercepting or hiding earlier wills.

Handwriting experts and solicitor records are often used to investigate.

5. Lack of Knowledge and Approval

Even if the will was properly signed, siblings can challenge it if the parent did not fully understand its contents.

This often arises when:

• One sibling arranged the will,
• The parent had limited literacy or English skills,
• The will was unusually favourable to one child,
• The parent signed without reading it due to illness or pressure.

6. Inheritance Act 1975 Claims (for Financial Provision)

Siblings can also claim financial provision if:

• They were financially dependent on the parent,
• They lived with the parent,
• They contributed to the household or care,
• They were treated as part of the family unit.

This type of claim does not challenge the validity of the will, it asks the court to redistribute the estate fairly.

Signs a Sibling May Have Grounds to Contest a Will

You may have a strong claim if:

• The will was changed shortly before death,
• One sibling received a disproportionate share,
• A sibling had control over the parent’s finances,
• The parent was isolated from other children,
• There are inconsistencies between earlier wills,
• The parent was vulnerable, ill, or reliant on one child.

Sibling disputes often involve a combination of emotional history and legal irregularities.

What Siblings Should Do If They Want to Dispute a Will

1. Gather Evidence Early

Useful evidence includes:

• Previous versions of the will,
• Medical records,
• Emails, texts, or letters,
• Financial documents,
• Notes from the solicitor who drafted the will,
• Statements from relatives or carers.

The more detailed the evidence, the stronger your position.

2. Enter a Caveat (If Challenging Validity)

A caveat prevents probate from being issued, giving siblings time to investigate concerns. It lasts six months and can be renewed.

3. Seek Specialist Contentious Probate Advice

Sibling disputes are often emotionally charged and legally complex. A solicitor can:

• Assess whether you have a strong claim,
• Identify the correct legal grounds,
• Gather expert evidence,
• Communicate with the executor (often another sibling),
• Begin negotiations or mediation.

Most sibling disputes settle before reaching court.

How a Specialist Solicitor Helps in Sibling Disputes

A contentious probate solicitor can:

• Analyse family dynamics and potential undue influence,
• Review medical and legal evidence,
• Protect the estate from being distributed prematurely,
• Navigate strict deadlines,
• Support negotiations between siblings to avoid long‑term family breakdown.

Get Help Today

If you believe a sibling has unfairly influenced a will, or you’ve been left out unexpectedly, early legal advice is crucial.

Contact our team to:

• Arrange a free consultation,
• Explore No Win No Fee options,
• Speak with solicitors experienced in sibling inheritance disputes.

📞 Call us at 0333 358 3034 or visit our contact page to get started.