Understanding Mutual Wills: What Couples Need to Know

4^th November, 2025

Blended families often face unique challenges when it comes to estate planning. Parents may wish to ensure that, after both die, their assets are distributed fairly among all children: biological, adopted, or stepchildren. However, the surviving spouse may later change their Will in a way that excludes some children. Fortunately, Mutual Wills can provide an important mechanism to prevent this.

What Are Mutual Wills?

A Mutual Will exists when two people, typically spouses or partners, enter into a binding agreement to make Wills in a certain form and not to revoke or change them without the other’s consent. Once one spouse dies, the surviving spouse is contractually bound by the agreement. If the surviving spouse alters their Will in breach of the agreement, a court may enforce the contract.

Why Mutual Wills Matter

Without a Mutual Will agreement, it can be very difficult for beneficiaries to prove the deceased’s original intentions. Courts look for clear evidence of an agreement, such as a deed of Mutual Wills or a formal contract. This evidence ensures that the estate plan is respected and reduces the risk of disputes among beneficiaries.

Interaction with Family Provision Laws

It is also vital to understand that Mutual Wills do not override statutory family provision laws. In Barns v Barns [2003] HCA 9, the parties had entered into a deed of Mutual Wills under the Inheritance (Family Provision) Act 1972 (SA). The High Court held that the property subject to the agreement was still part of the estate for a family provision claim. Thus, even with a Mutual Will agreement, eligible persons may still seek orders for further provision.

 Practical Considerations

Mutual Wills are particularly useful in blended families where spouses want to ensure their estate passes according to a shared plan. However, they can be complex and more expensive to prepare than standard Wills. It is important to ensure intentions are clearly recorded, agreements are professionally drafted, and beneficiaries understand the arrangement. Open communication can also reduce the risk of disputes.

Mutual Wills provide additional control over estate distribution, but statutory family provision rights can still interfere. Professional legal advice is essential to create enforceable agreements and tailored estate plans.

How We Can Help

Our team understands the unique needs of blended family situations. The team at Castrikum Adams Legal can help you prepare draft clear Mutual Wills in Byron Bay, Ballina, Murwillumbah, Lismore and Bangalow. Contact us today to secure your family’s future with confidence.

Disclaimer: The cases referenced in this blog are publicly available information and are not matters on which our firm has worked or provided representation for. This content is intended for general informational purposes only and does not constitute as legal advice.