What Is a Marriage Contract in Canada? How It Differs from a US Prenup

If you search Canada for "marriage contract" instead of "prenup," you're not confused — you're using the correct legal term. Most Canadians still call it a prenup, but that word never appears in Canadian legislation. The legal term across the common law provinces is marriage contract, and in Quebec it is a contrat de mariage. This article explains exactly what a marriage contract in Canada is, how it works province by province, and how it compares to the US prenuptial agreement — including what matters most if you and your partner straddle the border.

What Is a Marriage Contract in Canada?

A marriage contract is the agreement two people sign before they marry to decide, in advance, how property, finances, and support will be handled if the marriage ends by separation, divorce, or death.

In Ontario, a marriage contract is one of the three types of domestic contracts set out in the Family Law Act. It is similar in concept to a "prenuptial agreement" or "prenup" as that term is used in the United States. A marriage contract can be entered into prior to marriage or at any time before the marriage breaks down.

That last point is significant. A marriage contract in Canada can be signed before or during marriage, which means it can function as either a prenup or a postnup. The single document covers both scenarios under one legal umbrella — something that varies considerably in the US, where prenups and postnups are treated as distinct instruments with different scrutiny levels.

The Three Types of Domestic Contracts

Under Canadian provincial family law, a marriage contract sits within a broader family of agreements:

• Marriage contract (pre-marriage) — signed before the wedding, by a couple who intend to marry; this is the Canadian legal equivalent of what Americans call a prenuptial agreement, though the term "prenuptial agreement" does not appear in Canadian legislation
• Marriage contract (post-marriage) — signed after the wedding, during the marriage; the equivalent of what Americans call a postnuptial agreement
• Cohabitation agreement — for couples in a common-law relationship

The distinction between the first two comes down to timing, not legal substance. In most Canadian provinces, both pre- and post-marriage agreements are governed by the same legislation and produce the same legal effect — in Ontario, for example, both fall under Part IV of the Family Law Act and are treated as "domestic contracts." The only practical difference is the date of signing.

If you're in a common-law relationship and wondering whether a similar agreement applies to you, see our guide on Common-Law Marriage and Prenups: What Couples Need to Know.

What Can a Marriage Contract Cover in Canada?

Marriage contracts governed by provincial family law statutes can address matters such as ownership and division of property, treatment of debts, spousal support rights or waivers, rights to the matrimonial home (subject to some statutory limits), and financial arrangements during the marriage.

What they cannot do is equally important. Marriage contracts cannot determine decision-making responsibility or parenting time for children, nor can they be used to contract out of a child's right to support. This is a firm limit across all Canadian provinces. Courts treat children's interests as non-negotiable — no private contract can override what a judge determines is in a child's best interest at the time of separation.

It is also important to note that provincial marriage contracts interact with the federal Divorce Act. Even where a marriage contract includes a spousal support waiver that is valid under provincial law, a court hearing a divorce proceeding may override that waiver under the Divorce Act if enforcing it would leave a spouse in circumstances not in accordance with the Act's support objectives. Parties should not assume a contractual support waiver is immune from judicial review at the federal level.

For a deeper look at how children affect your agreement, read What Happens to a Prenup When You Have Children?

Canadian marriage contracts can also address what happens to registered accounts like RRSPs and TFSAs — assets that have no direct equivalent in the US system. See How a Prenup Can Protect Your RRSP and TFSA in Canada for a full breakdown.

Validity Requirements: What Makes a Canadian Marriage Contract Enforceable?

In Ontario, validity requires that the domestic contract be in writing, signed by both parties, witnessed, and dated. British Columbia has similar requirements under section 93 of its Family Law Act, which requires written form, signatures, and witnessing by at least one person.

Beyond the formal requirements, courts look at the substance of how the agreement was made. A marriage contract that is supported by full financial disclosure, where each party received independent legal advice, was signed without pressure, and is not unconscionable on its face, will generally be enforced by a court — even if the outcome later feels unfair to one spouse.

Courts may set aside a contract (or parts of it) if it is fundamentally unfair, if disclosure was insufficient, or if the agreement was signed under duress.

Independent legal advice (ILA) — where each party retains their own lawyer — is not always a statutory requirement, but its absence is routinely the reason agreements fail. New Brunswick's Family Law Act contains provisions allowing a court to disregard a term where a spouse did not receive independent legal advice and enforcing the term would be inequitable — a stricter approach than Ontario's, where independent legal advice is not formally required by statute but its absence is a leading reason agreements are successfully challenged. Readers relying on New Brunswick law should consult the specific provisions of that Act and seek advice from a New Brunswick family lawyer, as the precise statutory standard is subject to judicial interpretation.

Two Supreme Court of Canada decisions are frequently cited in enforceability disputes and are worth knowing. Hartshorne v. Hartshorne, 2004 SCC 22, involved a marriage agreement signed shortly before the wedding but also addressed in the context of post-marriage circumstances — it is not strictly a prenuptial agreement case, and practitioners should read it with that nuance in mind. Miglin v. Miglin, 2003 SCC 24, dealt with a separation agreement rather than a pre-marriage contract, but established an important two-stage framework for assessing whether courts should override domestic agreements. Both decisions inform how Canadian courts approach the enforceability of marriage contracts, though neither arose from a classic pre-marriage prenuptial agreement scenario.

How Quebec Is Different: The Contrat de Mariage

Quebec operates under civil law rather than common law, and its rules are meaningfully different from every other province.

In Quebec, the agreement is referred to as a marriage contract (contrat de mariage), governed by the Civil Code of Québec, which provides a distinct legal framework compared to other Canadian provinces.

The biggest structural difference is the matrimonial regime system. A marriage contract in Quebec allows prospective spouses to choose a matrimonial regime. The default regime is the partnership of acquests (régime de la société d'acquêts). Under this default, property each spouse owned before the marriage and anything received by gift or inheritance stays separate, while assets accumulated during the marriage are shared on dissolution.

There are two predominant types of matrimonial regime: the regime of separation as to property and the regime of partnership of acquests. If you marry under the regime of separation as to property, you must have a marriage contract. If you marry under the regime of partnership of acquests, you are not required to have a marriage contract, but you may draw one up if you wish.

Critically, Quebec also has a unique formal requirement that sets it apart from every other province: to be legally valid, a marriage contract in Quebec must be executed before a notary as a notarial act in minute. A simple signed-and-witnessed document — sufficient in Ontario or BC — is not enough in Quebec. For certain matters in Quebec, it is a notary (rather than a lawyer) who performs this function.

How a Canadian Marriage Contract Differs from a US Prenup

If you've been researching prenups using American sources, some of what you've read may not apply north of the border. Here are the key differences.

Terminology and Legal Framework

In the US, the agreement signed before marriage is universally called a prenuptial agreement (or premarital agreement). Prenuptial agreements are recognized across the United States, though the statutory framework varies significantly by state. Approximately 28 states plus D.C. had adopted the Uniform Premarital Agreement Act (UPAA) or the updated Uniform Premarital and Marital Agreements Act (UPMAA) as of the most recent available data, with additional adoptions occurring in recent years — readers should verify current adoption status with the Uniform Law Commission. In Canada, there is no equivalent uniform federal statute. Property division on separation is governed by each province's own family law statute — Ontario's Family Law Act, British Columbia's Family Law Act, and so on.

Timing Flexibility

In the US, a prenup is specifically a pre-marriage instrument; a post-marriage version is a separate postnuptial agreement, and courts in many US jurisdictions apply heightened scrutiny to postnuptial agreements because spouses owe each other fiduciary duties during marriage. Recognition and enforceability of postnuptial agreements varies by state, and the legal landscape continues to evolve.

In Canada, the same domestic contract legislation covers both pre- and post-marriage agreements under the single label of "marriage contract," with no automatic increase in judicial suspicion based purely on timing.

Notarization

Most US states do not require notarization of a prenup — a signed, witnessed writing is typically sufficient. In Quebec, notarization before a notary is mandatory. In the rest of Canada, notarization is not required, and a marriage contract does not need to be filed with any government office to take effect between the spouses.

Children and Support

Both countries share the same hard limit: neither a US prenup nor a Canadian marriage contract can waive or predetermine child support. Courts on both sides of the border reserve that question for the time of separation, based on the child's actual needs and circumstances.

The "Second Look" Doctrine

A number of US states apply some form of "second look" doctrine, under which a court can refuse to enforce a prenup that was fair when signed but has become unconscionable by the time of divorce. Massachusetts is a well-known example. Canadian courts have their own version of this fairness review — even if a contract meets formal legal standards, a court may refuse to enforce it if it would lead to an unconscionable outcome, particularly in light of current circumstances compared to those when the contract was signed.

Province-by-Province Snapshot

Rules vary enough that your province matters enormously. The table below covers the most commonly searched provinces; Alberta, Manitoba, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and the territories are not included here and each has its own governing legislation. If you are in one of those jurisdictions, consult a local family lawyer for province-specific advice.

Note on missing provinces: Manitoba, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and the territories each have their own family property legislation governing marriage contracts. Residents of those jurisdictions should seek advice from a local family lawyer rather than relying on the provincial comparisons above.

What Does a Marriage Contract Cost in Canada?

Cost is one of the most common questions Canadians ask when researching marriage contracts, and the honest answer is that it varies considerably. For a straightforward agreement between two parties with relatively simple finances, legal fees in Canada typically range from approximately $1,500 to $3,500 per couple when both parties retain their own lawyers — which is strongly recommended. More complex agreements involving business interests, significant real estate holdings, or cross-border assets can cost $5,000 to $10,000 or more in total legal fees. Quebec adds the cost of the notary's fees on top of any legal advice obtained beforehand. These figures are general estimates; actual costs depend on the lawyers retained, the complexity of the agreement, and the province. Request a fee estimate from your lawyer before engaging them.

What Happens If You Move Provinces?

A marriage contract validly executed in one Canadian province does not automatically lose its legal effect if you move to another province, but the new province's courts will apply their own family law legislation when assessing enforceability. For example, an Ontario marriage contract that validly waives equalization under Ontario's Family Law Act may be interpreted differently by a British Columbia court applying BC's Family Law Act regime. Courts in the new province will generally respect a properly executed agreement but will apply local standards for unconscionability, disclosure, and fairness. Cross-provincial moves are a real and underappreciated risk — if you relocate, have your existing agreement reviewed by a lawyer in your new province of residence.

Cross-Border Couples: What You Need to Know

If one partner is Canadian and the other is American — or if you split time between the two countries — a single agreement may not automatically protect you in both jurisdictions. For a marriage contract to be valid in both the US and Canada, couples should draft a clear, written contract addressing property and financial rights that complies with each country's legal requirements, including full financial disclosure.

The practical advice is to retain lawyers in both jurisdictions, or at minimum have the agreement reviewed by counsel in each country. What is enforceable in California may not map cleanly onto Ontario's equalization regime, and vice versa. Cross-border couples with immigration considerations should also read Prenups and Immigration: Protecting Yourself When Sponsoring a Spouse.

What a Marriage Contract Cannot Do

It's worth being explicit about the limits, because overreach is one of the most common reasons Canadian marriage contracts are set aside:

• Child support and parenting time — courts will not enforce these provisions; they are set at the time of separation based on the child's best interests
• Matrimonial home possession rights — in Ontario, certain statutory rights to possess the matrimonial home cannot be contracted away
• Spousal support waivers under the federal Divorce Act — even a valid provincial waiver may be overridden by a court applying the Divorce Act in divorce proceedings
• Unconscionable terms — a court can strike down any term that shocks the conscience, regardless of whether both parties signed willingly
• Terms obtained by duress or without disclosure — a court may set aside the agreement if one party failed to disclose or undervalued their assets

Frequently Asked Questions

Is a marriage contract the same as a prenup in Canada? Functionally, yes. A marriage contract signed before the wedding serves the same purpose as what Americans call a prenuptial agreement. The difference is purely terminological: "prenuptial agreement" does not appear in Canadian legislation, while "marriage contract" does.

Can a marriage contract be signed after the wedding in Canada? Yes. Unlike in the US, where a post-marriage agreement is a separate legal instrument called a postnuptial agreement, Canadian provincial legislation allows a marriage contract to be signed before or during the marriage under the same legal framework.

How much does a marriage contract cost in Canada? For a straightforward agreement, expect combined legal fees in the range of $1,500 to $3,500 when both parties retain independent lawyers. Complex agreements can cost significantly more. Quebec adds notarial fees.

What makes a marriage contract invalid in Canada? Common grounds for setting aside a marriage contract include lack of financial disclosure, absence of independent legal advice, duress or undue pressure at signing, and terms that are unconscionable at the time of enforcement.

Does a marriage contract cover what happens to my RRSP or TFSA? Yes, registered accounts can be addressed in a marriage contract. See our dedicated guide on How a Prenup Can Protect Your RRSP and TFSA in Canada.

Getting Started

A marriage contract in Canada is a serious legal document, and the gap between a well-drafted one and a poorly drafted one can be the difference between a court enforcing it and setting it aside entirely. The core requirements — full financial disclosure, independent legal advice for each party, no pressure, and a written signed witnessed document — are consistent across common law provinces. Quebec adds the mandatory notary step.

If you're wondering about timing, What's the Best Time to Bring Up a Prenup in a Relationship? walks through the conversation practically. And if you're already engaged and feeling behind, Is It Too Late to Ask for a Prenup After the Wedding Is Planned? addresses that directly.

The terminology may differ from what you've seen in American media, but the underlying purpose is the same: a clear, fair agreement that protects both partners and reduces conflict if the marriage ends.

This article is for general information only and is not legal advice. Consult a qualified family lawyer in your province — or a notary if you are in Quebec — before drafting or signing a marriage contract.