Mirror Wills and Mutual Wills (NSW)

By James Stevens, Director and Solicitor, Go To Court Lawyers. Last reviewed 15 April 2026.

Many couples approach estate planning as a joint activity, engaging a solicitor to prepare wills and signing them together. For those couples, the most common options are mirror wills and mutual wills. While both types of testamentary instruments are used in those circumstances, they differ significantly in their purpose, legal nature, and enforceability. In New South Wales, the distinction between these two instruments has practical implications for estate administration and the rights of beneficiaries. This article explores the key differences between mirror wills and mutual wills, focusing on their characteristics, legal enforceability, common uses, and limitations in the context of NSW law.

What are mirror wills?

Mirror wills are two separate wills that contain identical or near-identical provisions, often created by couples who wish to leave their estates to each other and thereafter to the same beneficiaries, such as their children. Mirror wills are widely used by married couples, de facto partners, and others in close relationships to simplify estate planning and ensure consistency in their wishes. For example, spouses may use mirror wills to guarantee that their assets pass to each other and then to their children. Mirror wills have the following characteristics:

• each person has their own separate will, although the terms of both wills mirror each other
• each party retains testamentary freedom, including the right to revoke or amend their will at any time, even after the other party's death
• the wills typically include reciprocal provisions where each party leaves their estate to the other (for example, “I leave everything to my spouse”) and then to shared beneficiaries (for example, “upon the death of my spouse, the estate goes to our children”).

There are some notable limitations to mirror wills, in that either party can change their will at any time without notifying the other party. If the surviving party remarries or wishes to alter their estate plan after the other’s death, they are free to do so, thereby disinheriting the original beneficiaries.

What are mutual wills?

Mutual wills are similar to mirror wills in that they are often created by couples or close individuals, but they differ significantly in their binding nature. Mutual wills are underpinned by a legal agreement between the parties that neither will revoke or alter their will without the other party’s consent. Mutual wills are often used in situations where there is a strong need to ensure that specific beneficiaries inherit the estate. This is particularly common with blended families, where there is a wish to protect the inheritance rights of children from previous relationships, especially if the surviving party remarries.

Mutual wills can also be useful to ensure continuity in the ownership of family businesses or specific assets that might otherwise pass out of the family’s hands. Mutual wills are notable in that they:

• are created as part of a binding agreement between the parties, typically documented in writing. The agreement imposes an obligation on the surviving party to adhere to the terms of their mutual wills after the first party’s death;
• trigger a constructive trust after the death of the first party, in that the surviving party holds the estate on trust for the agreed beneficiaries. In NSW, the Supreme Court will impose the trust on the surviving party’s estate if they attempt to deviate from the terms; and
• are irrevocable after one party dies, in that the other party is legally bound to follow the terms of the mutual will, preventing unilateral changes.

In terms of limitations, mutual wills are more complex, and require clear documentation and legal advice to ensure enforceability. Disagreements may arise over the interpretation or implementation of the mutual wills agreement. The binding nature of mutual wills can be restrictive, especially if the surviving party's circumstances change significantly after the other party’s death.

When deciding between mirror wills and mutual wills, testators should carefully evaluate their goals, relationships, and the potential risks. Mirror wills are suitable for individuals who have a simple estate plan with common beneficiaries, such as shared children. They are appropriate for people who value flexibility and the ability to update their wills as circumstances change. Mutual wills are more suitable for situations where there is a strong need to ensure specific beneficiaries inherit particular assets, such as children from previous relationships. They are also used when testators have complex assets or family dynamics that require a binding commitment where both parties are willing to accept the restrictions imposed by the agreement.

By considering the unique needs of each situation and seeking professional advice, testators can choose the most appropriate approach to safeguard their legacy and provide appropriately for their loved ones. Please get in touch with Go To Court on 1300 636 846 for advice about which type of will is right for your circumstances.