Prenuptial agreements (often shortened to “prenups”) are becoming an increasingly popular way for couples in Canada to make decisions about property, debt, and financial responsibilities before getting married or entering into a long-term romantic partnership. They can provide clarity, reduce conflict, and help both partners feel more secure about their future.
But what happens when things go wrong? Can you challenge a prenup? Can a prenup be overturned after it’s been signed? What makes a prenup invalid?
In this post, we explore the legal grounds for challenging a prenuptial agreement in Canada and how courts decide whether a prenup is enforceable or not.
A prenuptial agreement (or “prenup”) is a type of domestic contract that couples sign before marriage to determine how property, assets, income, and debt will be managed during the relationship and in the event of a breakup or death. In some provinces, it’s called a marriage contract, but it means the same thing.
So, what is a prenup in practical terms?
It’s a written agreement that can cover things like:
While you can’t use a prenup to decide child custody or child support (those decisions are made based on the child’s best interests at the time of separation), you can use one to take control over many other aspects of your financial life.
Yes, but only if they meet specific legal requirements.
Prenups are recognized under provincial family laws across Canada. But to be legally binding and enforceable, a prenuptial agreement must be:
So, are prenups legally binding in Canada? Generally, yes, but they’re not bulletproof. If the prenup doesn’t meet legal standards, or if it seems deeply unfair, it may not be enforceable.
Yes. Challenging a prenuptial agreement is possible in Canada, and courts do overturn them under the right circumstances.
So if you’re asking:
The answer is: it depends.
As far as what makes a prenup invalid, courts will look at the circumstances in which the prenup was created and signed, as well as the content of the agreement itself. If there are concerns about fairness, pressure, or missing information, the agreement may be at risk.
Let’s break down the most common legal reasons for contesting a prenuptial agreement in Canada.
There are several legal arguments that can be used to challenge a prenup. If any of the following issues are present, the court may decide that the agreement is invalid or unenforceable.
When signing a prenup, each person is expected to disclose all their assets, debts, income, and liabilities.
If someone hides something like a major debt, property, or business, the agreement can be set aside.
Why it matters: You can’t make an informed decision about your future if you don’t know the full financial picture. Courts take this very seriously. Never hide anything about your finances from your partner when you’re creating a prenup.
Was the agreement signed just days before the wedding? Did one person feel emotionally pressured or threatened into signing?
If a prenup was signed under duress, the court may find that it wasn’t truly voluntary.
Examples of coercion might include:
While not always legally required, independent legal advice (ILA) can help ensure each person fully understands the prenup before signing.
If only one person had a lawyer, the court may question whether the other person truly understood the agreement.
Using a lawyer-informed platform like Jointly can reduce these risks by ensuring the prenup meets legal standards. But for maximum protection, ILA is still recommended. We include a certificate of ILA as an attachment to every Jointly agreement that you can take to a lawyer in your area.
Even if an agreement meets all the formal requirements, a court may strike it down if it’s extremely unfair.
If the prenup heavily favours one person or denies the other support or property without justification, it may be considered “unconscionable.”
The court may ask:
For example, imagine a scenario where one person gives up their career in order to move across the country to an area where the other person has significantly more career opportunities. A prenup that does not take into account the career sacrifices made through either spousal support or property division is unlikely to be seen as fair by the court.
Did the prenup meet all legal formalities?
If the agreement wasn’t signed, witnessed, or dated properly, the court might find it invalid.
While this seems technical, these details matter especially when a relationship ends and the prenup is being relied on.
In rare cases, courts may overturn a prenup if circumstances have changed so drastically that it would be unfair to enforce the original terms.
This might happen if:
While courts are generally reluctant to intervene, major shifts can open the door to challenging a prenuptial agreement. This is why it’s important to review your prenup regularly, and update it as needed as your circumstances change.
Courts assess challenges to prenuptial agreements by looking at two main things:
When deciding whether to uphold or strike down a prenup, a judge will consider:
The burden of proof is on the person who wants to challenge the agreement. That means they need to provide evidence of duress, hidden assets, or other legal flaws.
If you want your prenup to hold up in court, follow these best practices:
If a court decides that a prenuptial agreement is invalid or unenforceable, the agreement won’t be used to decide financial issues. Instead, provincial or territorial family laws will apply.
That usually means:
These default rules aim to be fair but they may not reflect what you and your partner would have chosen.
That’s why a valid prenup matters. It gives you control over your financial future rather than leaving it in the hands of legislators and the courts.
Are prenups legally binding in Canada? Yes, but they’re only as strong as the process used to create them.
Whether you’re wondering what is a prenuptial agreement, can a prenup be challenged, or what makes a prenup invalid, the bottom line is this: a well-crafted, fair, and transparent prenup is much more likely to be enforceable.
If you’re thinking about creating a prenup that will stand up in court or you’re concerned that your current one might not, Jointly can help. Our online platform offers a guided, legally-informed process to help couples create clear, balanced agreements from the start.
Take control of your relationship’s future together.
Aimee SchallesHi, I'm Aimee, a co-founder of Jointly. I’ve been working as a lawyer in British Columbia for over ten years. I run a small law firm and love helping people solve everyday problems. I’ve seen the difficulties that ordinary people face in accessing reliable legal services. I’ve also seen many friends and clients go through challenging separations that could have been improved if they’d have had a prenup or cohabitation agreement. I hope Jointly helps people make the relationship agreement they’ve been thinking about! Latest posts by Aimee Schalles (see all)