Mutual Wills and Mirror Wills: What Is the Difference?

by | Sep 29, 2025

Make sure your wishes are followed by choosing the right type of will.

Following on from a previous article about trusts, I thought it would be good to consider another part of generational planning- the use of will. 
 
I will break this down into two articles, the first (this one) discusses the difference between mutual and mirror wills and why this difference is important to understand– this is not country specific. The second article will look at how this could apply in the Czech Republic. 

What are Mirror Wills?

A pair of wills (usually made by spouses or partners) that reflect each other — typically leaving everything to the surviving partner, and then to the same chosen beneficiaries (e.g., children).

The key issue here is that mirror wills are not legally binding on the survivor and so if one partner dies, the other is then free to change their will to whatever they want- which may not have been the original plan agreed between both parties. 

If we consider an example

John and Mary each write a will leaving everything to each other. After the second death, their estate goes equally to their children.

In a mirror will, if John dies first, Mary can later change her will to leave assets to someone else if she chooses- which could include a future spouse and the children of that spouse and not John’s children. 

What are Mutual Wills?

While mutual wills are, again, drawn up to reflect each other these are special agreements to make wills on agreed terms, with a legally binding promise not to change them after the first death.

Effectively, this is a binding contract between the two parties. When the first person dies, the survivor is legally prevented from altering the will.

Looking at John and Mary again

John and Mary agree that after both die, their estate must go equally to their children. John dies first. Mary inherits, but she is not allowed to change her will later to exclude the children or favour someone else. 

Summary

The difference:

Mirror wills – look alike, but are revocable and flexible. 

Mutual wills – contractually binding, survivor cannot change terms after the first death. 

If you have a large estate, it may well be worth discussing LINK Czech Trusts and Inheritance Tax with a lawyer and a financial adviser.

The views expressed in this article are not to be construed as personal advice. Therefore, you should contact a qualified, and ideally, regulated adviser in order to obtain up-to-date personal advice with regard to your own personal circumstances. Consequently, if you do not, then you are acting under your own authority and deemed “execution only”. The author does not accept any liability for people acting without personalised advice, who base a decision on views expressed in this generic article. Importantly, where this article is dated then it is based on legislation as of the date. Legislation changes but articles are rarely updated, although sometimes a new article is written; so, please check for later articles or changes in legislation on official government websites, as this article should not be relied on in isolation.

Vyjádřené názory v tomto článku nelze považovat za osobní poradenství. Vždy se proto obraťte na kvalifikovaného, ideálně regulovaného poradce, který vám poskytne aktuální, osobní doporučení šitá na míru vaší konkrétní situaci. Pokud se rozhodnete jednat bez takového poradenství, činíte tak na vlastní odpovědnost a vaše jednání spadá pod režim „execution only“ (pouhá realizace pokynu bez poradenství). Autor nepřijímá žádnou odpovědnost za rozhodnutí osob, které se spoléhají na názory uvedené v tomto obecném článku bez personalizovaného poradenství. Je důležité si uvědomit, že pokud je článek datován, vychází z právních předpisů platných k uvedenému datu. Právní předpisy se mohou měnit a články jsou aktualizovány jen zřídka. Doporučujeme proto vždy ověřit případné novější články nebo změny legislativy na oficiálních vládních stránkách, protože na tento článek nelze spoléhat izolovaně.

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Post written by:
Autorem článku je:

Chris Lean

In the UK he worked with accountants as an independent financial adviser, qualified as a Chartered Financial Planner and became an examiner for the Chartered Insurance Institute. He also qualified as a European Financial Planner and specializes in investment and pension advice to clients.

Aisa International is the only financial advice service company specialising in advice for expats that is regulated as a Securities Trader in the Czech Republic, USA, and UK.