- An Ontario court can set aside a domestic contract on three grounds: failure to disclose significant assets or debts, not understanding the contract, or general contract law reasons.
- A clause saying the contract can never be challenged does not remove the court's power to set it aside.
- Support waivers, child support and parenting terms face extra checks, so parts of a prenup can fail even if the rest stands.
You signed a prenup, and now your marriage is ending. You may be wondering whether the agreement really binds you, or whether a court can ignore it. The short answer is that Ontario courts usually expect people to follow what they signed, but the law gives them power to set a contract aside in certain situations.
In Ontario, a prenup is formally called a marriage contract, and the Family Law Act does not use the word prenup. This article explains the grounds a court can use, how support and children's terms are treated differently, and what to gather if you are thinking about challenging an agreement.
The starting point: a signed contract is meant to be followed
Ontario's government guidance says that once a marriage contract is signed, the couple must follow it. To be enforceable at all, a domestic contract must be in writing, signed by the parties and witnessed. A contract that misses those formal steps may be unenforceable before anyone gets to the grounds below.
A domestic contract can also deal with a matter that the Family Law Act covers, and in that case the contract prevails unless the Act provides otherwise. That is why a prenup can change how property is divided, and also why the exceptions in the Act matter so much.
The three grounds in section 56(4)
On application, a court may set aside a domestic contract, or a provision in it, on three grounds. The court can set aside just a provision, so the rest of the contract may survive.
| Ground | In plain words |
|---|---|
| Section 56(4)(a): non-disclosure | A party failed to disclose significant assets, or significant debts or other liabilities, that existed when the contract was made. |
| Section 56(4)(b): lack of understanding | A party did not understand the nature or consequences of the contract. |
| Section 56(4)(c): contract law | Otherwise in accordance with the law of contract. |
The third ground is the statutory route for arguments such as duress or pressure to sign. The Act does not deal with timing or pressure by name, so judges decide those arguments case by case on the facts.
Hidden assets, misunderstanding and pressure
Non-disclosure is about significant items that existed when the contract was made, such as a major asset or a large debt. The statute does not set a list of documents that must be exchanged, so what counts as significant depends on the situation. Ontario's government does advise partners to exchange financial information before signing.
A lack of understanding argument asks whether you grasped what the contract did and what its results would be. Duress or pressure is argued under the contract law ground, and the outcome depends on the evidence about how the contract came to be signed.
A clause stating that you cannot challenge the contract does not help the other side. Section 56(4) applies despite any agreement to the contrary.
Terms about support and children get extra scrutiny
Some terms can be reviewed even if none of the three grounds applies. A court may set aside a support provision, or a waiver of the right to support, if it results in unconscionable circumstances. It may also do so if the provision is in favour of, or the waiver is by or on behalf of, a dependant who qualifies for support out of public money. A support provision may also be set aside if support under the contract is in default when the application is made.
For divorcing spouses, the federal Divorce Act treats an agreement about support as a factor the court weighs, not a bar to support. Child-related terms are also reviewable. A court may disregard a term about a child's education, moral training, decision-making responsibility or parenting time if that is in the child's best interests. It may disregard a child support term that is unreasonable having regard to the child support guidelines.
- Property terms are mainly tested under the section 56(4) grounds.
- Spousal support waivers can also be tested under section 33(4).
- A court may disregard a term about a child's education, moral training, decision-making responsibility or parenting time if that is in the child's best interests, and a child support term that is unreasonable having regard to the child support guidelines.
What to do next
If you are thinking about challenging a prenup, start by collecting the facts that a court would look at. A lawyer can tell you how those facts fit the grounds, and whether time limits could affect any property claim. For example, an equalization application must be brought by the earliest of two years after divorce or nullity, six years after separation, or six months after the first spouse's death, although a court may extend some time limits.
- A copy of the signed contract, with the signature and witness pages
- Emails and messages about how and when the contract was presented and signed
- Any financial information you received, or did not receive, before signing
- Records of the assets and debts each of you had on the date you signed
- Notes on who advised you, if anyone, and how much time you had to review it
Frequently asked questions
Can a prenup be thrown out in Ontario?
A court may set aside a domestic contract, or part of it, on application, on the grounds set out in the Family Law Act. Those include non-disclosure of significant assets or debts, not understanding the contract, or other contract law reasons. Support waivers and child-related terms can also be reviewed on separate grounds. Whether your facts fit depends on the evidence.
Does a no-challenge clause stop me from going to court?
No. The court's power to set a contract aside applies despite any agreement to the contrary, so a clause cannot remove it.
Is a prenup invalid if I had no lawyer?
The formal requirements are writing, signatures and a witness, and a lawyer is not one of them. Ontario's government still advises each partner to speak to a different lawyer and to exchange financial information before signing. How missing advice affects a particular case depends on the facts, so it is worth confirming with a lawyer.
Can a prenup waive spousal support?
A contract can include a support waiver, but a court may set it aside if it results in unconscionable circumstances, or on the other grounds in section 33(4). A lawyer can tell you how that applies to your situation.
Sources
- Ontario.ca – Dividing property when a marriage or common law relationship ends — ontario.ca
- Family Law Act, s. 55(1) — Ontario e-Laws
- Divorce Act, s. 15.2(4)(c) — Justice Laws (federal)
Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.
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