Marriage Contracts and Wills in Canada — How They Work Together
When two people marry later in life, each often arriving with children, a home, and savings from a first chapter, the question is rarely whether they love each other — it is what happens to the house and the RRSPs if the marriage ends or one of them dies. A marriage contract answers the first half of that question. A will answers the second. The mistake is assuming either document does the other's job. They are two instruments playing in the same orchestra, and they have to be written to the same score.
This guide explains what a marriage contract or cohabitation agreement can and cannot do, how it meshes with your will, and why the pairing matters most in blended families. It is general information for the common-law provinces and territories, not advice on your contract; domestic contracts are highly province-specific and benefit from a family lawyer.
What a domestic contract is
A marriage contract (for married couples) and a cohabitation agreement (for common-law couples) are forms of domestic contract recognized under provincial family law.[1] In one, a couple can set out how property and support are handled during the relationship and on its breakdown, and can confirm that specified assets — a business, a pre-marital home, an expected inheritance — remain the separate property of one partner.
What surprises people is how far into estate territory these contracts can reach.
What a contract can settle at death
A domestic contract can include estate provisions. Two are especially useful:
- Waiving the family-property election. In Ontario and some other provinces, a surviving married spouse can elect to take an equalization of net family property instead of what the will leaves them.[2] A marriage contract can have the spouses agree not to make that election, so the will's plan is not overridden on death — a frequent need in second marriages.
- Mutual releases. Each partner can release claims against the other's estate, clarifying that the contract, not a later dispute, governs.
- Setting your own property-division terms. Some provinces take a different structural approach. British Columbia's Family Law Act, for example, lets spouses agree how family property and debt will be divided — equally, unequally, or by excluding or including specific items — rather than relying only on the default rules.[3] A marriage agreement can use that flexibility to lock in a division that also serves the estate plan.
These provisions shape the estate; they do not constitute the estate plan. That is the will's job.
How the contract and the will work together
Think of the contract as the rules of the game and the will as the play you actually run. The contract defines what is separate, what each spouse can claim, and what they have given up; the will then distributes your assets within those boundaries. Coordination is essential — a will that breaks a promise made in the contract (for example, leaving away property the contract said a spouse would receive) can trigger a claim against the estate. Draft and review them together, and revisit both when circumstances change.
Why this matters most in blended families
The classic blended-family failure is leaving everything to a new spouse and trusting that the children of a first marriage will eventually be looked after. Once the new spouse inherits outright, they generally control it and can leave it to their own children. A marriage contract — confirming separate property and limiting the new spouse's claims on death — paired with a will or a spousal trust that provides for the spouse during life with the remainder to your children, is the durable solution. The contract protects the plan; the will (or trust) delivers it.
Making the contract stick
A domestic contract is only as strong as the process behind it. Generally it should be:
- In writing, signed, and witnessed.
- Supported by full financial disclosure — each partner shows the other what they own and owe.
- Made with independent legal advice for each party.
- Free of duress — not sprung days before the wedding.
Courts can set a contract aside for non-disclosure, unfairness, or improper pressure, so the shortcuts that feel efficient at signing are exactly what unravel the protection later.
The limits
A domestic contract is powerful but not absolute. It generally cannot bargain away child support, courts retain authority to override unfair terms, and in some provinces it cannot completely extinguish a dependant's right to claim support from an estate. Treat it as a strong layer of protection that works alongside a current will, not as a force field.
What we focus on at It's Simple Will
The Will Creator produces the will half of this pairing — the document that actually distributes your estate. A marriage contract is a family-lawyer exercise, and where one exists, your will should be drafted to fit it. Our guides aim to help you arrive at both conversations knowing how the pieces connect. For the property side of relationship breakdown, see inheritance and divorce in Canada.
Related guides
Citations & sources
- [1]Family Law Act, RSO 1990, c F.3, Part IV — domestic contracts — Government of Ontario
- [2]Family Law Act, RSO 1990, c F.3, s 6 — surviving spouse's election on death — Government of Ontario
- [3]Family Law Act, SBC 2011, c 25 — agreements respecting property division — BC Laws, Government of British Columbia
Frequently asked questions
What is a marriage contract or cohabitation agreement?
It is a domestic contract under provincial family law in which a couple sets out how property and support will be handled, both during the relationship and on breakdown, and often on death. Married couples use a marriage contract; common-law couples use a cohabitation agreement. They can confirm that certain assets remain separate property.
Can a marriage contract decide what happens when I die?
To a degree, yes. It can include estate provisions — for example, a spouse agreeing to waive a family-property election on death, or each partner releasing claims against the other's estate. But the contract does not dispose of your assets. You still need a will to say who inherits what.
How do a contract and a will fit together?
They are complementary. The contract sets the rules between you and your partner; the will distributes your estate within those rules. They must be coordinated so they do not contradict each other — a will that breaches an estate promise in a contract can lead to a claim against the estate.
Why are these contracts so useful in second marriages?
Because they can protect children from an earlier relationship. By confirming separate property and limiting a new spouse's claims on death, a contract — paired with a will or spousal trust — helps ensure your own children are not unintentionally disinherited when you remarry.
What makes a domestic contract valid?
Generally it must be in writing, signed and witnessed, made with full financial disclosure, and without duress. Independent legal advice for each party is strongly recommended. A court can set aside a contract for non-disclosure, unfairness, or improper pressure, so cutting corners undermines the very protection you want.
Are there limits on what these contracts can do?
Yes. They generally cannot bargain away child support, and courts can override unfair terms. In some provinces a contract cannot fully eliminate a dependant's right to claim support from an estate. Treat a domestic contract as strong protection, not an absolute shield.
Related reading
- Inheritance and Divorce in Canada — Is Your Inheritance Shared?
- Separation, Divorce and Your Will in Canada
- Naming Your Spouse as Sole Beneficiary in Canada — Pros and Pitfalls
- Joint-Partner (Joint-Spousal) Trusts in Canada — Probate Planning for Couples
- How to Write a Will in Canada — A Step-by-Step Guide by Province