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.
What is a Prenuptial Agreement In Canada?
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:
- Who owns what property (now and in the future)
- How property will be divided if the relationship ends
- Whether spousal support will be paid
- How debts will be handled
- What will happen to a shared home if the relationship ends
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.
Are Prenups Legally Binding In Canada?
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:
- Made in writing
- Signed voluntarily by both people
- Signed with full financial disclosure
- Signed in front of a witness
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.
Can A Prenup Be Challenged In Canada?
Yes. Challenging a prenuptial agreement is possible in Canada, and courts do overturn them under the right circumstances.
So if you’re asking:
- “Can a prenup be challenged?” or
- “Can a prenup be overturned?”
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.
Legal Grounds to Challenge 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.
Lack of Full Financial Disclosure
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.
Duress, Coercion, or Pressure
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:
- Threatening to call off the wedding unless the agreement is signed
- Rushing someone to sign without giving them time to think
- Using emotional manipulation, guilt or financial pressure
Lack of Independent Legal Advice
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.
Unconscionability or Gross Unfairness
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:
- Did the terms unfairly benefit one person at the other’s expense?
- Did one person make major sacrifices during the relationship that weren’t recognized?
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.
Procedural Issues
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.
Change in Circumstances
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:
- One partner became ill or disabled and needs financial support
- There was a significant change in financial situation or caregiving responsibilities
- One person made life-altering sacrifices based on expectations that are no longer realistic
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.
How Courts in Canada Assess Prenup Challenges
Courts assess challenges to prenuptial agreements by looking at two main things:
- Form – Was the agreement made properly? Is it written in clear and understandable language? Does it comply with provincial and federal law?
- Substance – Is the agreement reasonably fair, considering all of the circumstances?
When deciding whether to uphold or strike down a prenup, a judge will consider:
- Whether both parties entered into the agreement freely and voluntarily
- Whether both parties fully understood what they were signing
- Whether the agreement was grossly unfair at the time of signing (or has become unfair)
- Whether each person fully disclosed their financial situation
- Whether both people had legal advice or reasonable access to it
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.
How to Make a Prenup More Likely to Stand in Court
If you want your prenup to hold up in court, follow these best practices:
- Disclose Everything: Be honest and thorough. List all your assets, debts, income, and liabilities. Don’t hide anything.
- Start Early: Don’t wait until the week before the wedding. Give each person time to consider the agreement. Best practice is to start the conversation a few months before the wedding at the latest.
- Avoid One-Sided Terms: A prenup doesn’t need to be perfectly equal, but it should feel fair to both people, and take into account all contributions to the relationship (financial or otherwise).
- Follow Legal Formalities: The agreement must be in writing, signed by both people, and witnessed. It also has to be written in clear and understandable language that complies with provincial law. If you use Jointly, we’ll take care of the drafting for you!
- Get Legal Advice: If you can afford it, get independent legal advice. It’s not required in most provinces in order for your agreement to be valid, but it can be helpful. We’ve included a certificate of independent legal advice that you can take to a lawyer in your area with every Jointly agreement.
- Review After Major Life Events: If your financial situation or family structure changes significantly, revisit the prenup. You can change it by agreement at any time during your relationship.
What Happens if a Prenup Is Declared Invalid?
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:
- Equal division of family property
- Determination of spousal support based on need and contribution
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.
Final Thoughts
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.
- Grounds To Challenge A Prenuptial Agreement in Canada - June 2, 2025
- Marriage Contract Vs Prenuptial Agreement - May 30, 2025
- What Is A Marriage Contract? - May 29, 2025
